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Abstract:

An object of the invention is to provide a method for manufacturing a
substrate having a film pattern such as an insulating film, a
semiconductor film, or a conductive film with an easy process, and
further, a semiconductor device and a television set having a high
throughput or a high yield at low cost and a manufacturing method
thereof. One feature of the invention is that a first film pattern is
formed by a droplet discharge method, a photosensitive material is
discharged or applied to the first film pattern, a mask pattern is formed
by irradiating a region where the first film pattern and the
photosensitive material are overlapped with a laser beam and by
developing, and a second film pattern having a desired shape is formed by
etching the first film pattern using the mask pattern as a mask.

Claims:

1. A method for manufacturing a semiconductor device, comprising the steps
of:forming a first film pattern by discharging a conductive material with
a droplet discharge method;forming a first photosensitive material over
the first film pattern;forming a first mask pattern by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing;forming a gate
electrode having a desired shape by etching the first film pattern using
the first mask pattern as a mask;forming an insulating film and a
semiconductor film over the gate electrode;forming a second
photosensitive material over the semiconductor film;forming a second mask
pattern by irradiating the second photosensitive material with a laser
beam and by developing;forming a semiconductor region having a desired
shape by etching the semiconductor film using the second mask pattern as
a mask; andforming a source electrode and a drain electrode to be in
contact with the semiconductor region.

2. A method for manufacturing a semiconductor device, comprising the steps
of:forming a first film pattern by discharging a conductive material with
a droplet discharge method;discharging or applying a first photosensitive
material over the first film pattern;forming a first mask pattern by
irradiating a region where the first film pattern and the first
photosensitive material are overlapped with a laser beam and by
developing;forming a gate electrode having a desired shape by etching the
first film pattern using a the first mask pattern as a mask;forming an
insulating film and a first semiconductor film over the gate
electrode;forming a protective film over the first semiconductor
film;forming a second semiconductor film over the first semiconductor
film and the protective film;forming a second photosensitive material
over the second semiconductor film;forming a second mask pattern by
irradiating the second photosensitive material with a laser beam and by
developing;forming a semiconductor region having a desired shape by
etching the first semiconductor film and the second semiconductor film
using the second mask pattern as a mask; andforming a source electrode
and a drain electrode to be in contact with the semiconductor region.

3. A method for manufacturing a semiconductor device, comprising the steps
of:forming a first film pattern by discharging a conductive material with
a droplet discharge method;forming a first photosensitive material over
the first film pattern;forming a first mask pattern by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing;forming a source
electrode and a drain electrode having a desired shape by etching the
first film pattern using the first mask pattern as a mask;forming a
semiconductor film over the source electrode and the drain
electrode;forming a second photosensitive material over the semiconductor
film;forming a second mask pattern by irradiating the second
photosensitive material with a laser beam and by developing;forming a
semiconductor region having a desired shape by etching the semiconductor
film using the second mask pattern as a mask; andforming an insulating
film and a gate electrode over the semiconductor region.

4. A method for manufacturing a semiconductor device, according to any one
of claims 1 to 3, wherein the first photosensitive material and the
second photosensitive material are negative photosensitive resins.

5. A method for manufacturing a semiconductor device, according to any one
of claims 1 to 3, wherein the first photosensitive material and the
second photosensitive material are positive photosensitive resins.

6. A method for manufacturing a semiconductor device, according to any one
of claims 1 to 3, wherein one of the first photosensitive material and
the second photosensitive material is a negative photosensitive resin and
the other is a positive photosensitive resin.

7. A method for manufacturing a television set, comprising the steps
of:forming a first film pattern by discharging a conductive material with
a droplet discharge method;forming a first photosensitive material over
the first film pattern;forming a first mask pattern by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing,forming a gate
electrode having a desired shape by etching the first film pattern using
the first mask pattern as a mask;forming an insulating film and a
semiconductor film over the gate electrode;forming a second
photosensitive material over the semiconductor film;forming a second mask
pattern by irradiating the second photosensitive material with a laser
beam and by developing;forming a semiconductor region having a desired
shape by etching the semiconductor film using the second mask pattern as
a mask;forming a source electrode and a drain electrode to be in contact
with the semiconductor region; andforming a pixel electrode to be
connected to the drain electrode.

8. A method for manufacturing a television set, comprising the steps
of:forming a first film pattern by discharging a conductive material with
a droplet discharge method;forming a first photosensitive material over
the first film pattern;forming a first mask pattern by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing;forming a gate
electrode having a desired shape by etching the first film pattern using
the first mask pattern as a mask;forming an insulating film and a first
semiconductor film over the gate electrode;forming a protective film over
the first semiconductor film;forming a second semiconductor film over the
first semiconductor film and the protective film;forming a second
photosensitive material over the second semiconductor film;forming a
second mask pattern by irradiating the second photosensitive material
with a laser beam and by developing;forming a semiconductor region having
a desired shape by etching the first semiconductor film and the second
semiconductor film using the second mask pattern as a mask;forming a
source electrode and a drain electrode to be in contact with the
semiconductor region; andforming a pixel electrode to be connected to the
drain electrode.

9. A method for manufacturing a television set, comprising the steps
of:forming a first film pattern by discharging a conductive material with
a droplet discharge method;forming a first photosensitive material over
the first film pattern;forming a first mask pattern by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing;forming a source
electrode and a drain electrode having a desired shape by etching the
first film pattern using the first mask pattern as a mask;forming a
semiconductor film over the source electrode and the drain
electrode;forming a second photosensitive material over the semiconductor
film;forming a second mask pattern by irradiating the second
photosensitive material with a laser beam and by developing;forming a
semiconductor region having a desired shape by etching the semiconductor
film using the second mask pattern as a mask;forming an insulating film
and a gate electrode over the semiconductor region; andforming a pixel
electrode to be connected to the drain electrode.

10. A method for manufacturing a television set, according to any one of
claims 7 to 9, wherein the first photosensitive material and the second
photosensitive material are negative photosensitive resins.

11. A method for manufacturing a television set, according to any one of
claims 7 to 9, wherein the first photosensitive material and the second
photosensitive material are positive photosensitive resins.

12. A method for manufacturing a television set, according to any one of
claims 7 to 9, wherein one of the first photosensitive material and the
second photosensitive material is a negative photosensitive resin and the
other is a positive photosensitive resin.

13. A method for manufacturing a semiconductor device, according to any
one of claims 7 to 9, wherein the laser beam has any wavelength of from
ultraviolet light to infrared light.

14. A method for manufacturing a television set, according to any one of
claims 7 to 9, wherein the television set is a liquid crystal television
or an EL television.

15. A method for manufacturing a semiconductor device, comprising the
steps of:forming a first film pattern by a droplet discharge
method;forming a photosensitive material over the first film
pattern;forming a mask pattern by irradiating a region where the first
film pattern and the photosensitive material are overlapped with a laser
beam and by developing; andforming a second film pattern having a desired
shape by etching the first film pattern using the mask pattern as a mask.

16. A method for manufacturing a semiconductor device according to claim
1, further comprising the step of:forming a third film pattern to be
connected to the second film pattern by a droplet discharge method.

17. A method for manufacturing a semiconductor device according to claim
15, wherein the photosensitive material is a negative photosensitive
resin.

18. A method for manufacturing a semiconductor device according to claim
15, wherein the photosensitive material is a positive photosensitive
resin.

19. A method for manufacturing a semiconductor device according to claim
15, wherein the first film pattern is a conductive film.

20. A method for manufacturing a semiconductor device according to claim
15, wherein the second film pattern is at least one of a gate electrode,
a source electrode, or a drain electrode.

21. A method for manufacturing a semiconductor device according to claim
16, wherein the third film pattern is a wiring.

22. A method for manufacturing a semiconductor device according to claim
15, wherein the first film pattern is a semiconductor film.

23. A method for manufacturing a semiconductor device according to claim
15, wherein the second film pattern has a channel formation region,
source region, or a drain region.

24. A method for manufacturing a semiconductor device according to claim
15, wherein the first film pattern is an insulating film.

25. A method for manufacturing a semiconductor device according to claim
15, wherein the second film pattern is an insulating film having an
opening.

26. A method for manufacturing a semiconductor device, according to any
one of claims 1, 2, 3, and 15, wherein the laser beam has any wavelength
of from ultraviolet light to infrared light.

27. A semiconductor device comprising:a wiring formed by a droplet
discharge method; andan electrode connected to the wiring,wherein the
wiring has a width of 5 μm or less.

28. A semiconductor device comprising:a thin film transistor provided with
a gate electrode, a gate insulating film, a semiconductor region, a
source electrode, and a drain electrode; anda gate wiring connected to
the gate electrode,wherein the gate electrode has a width of 5 μm or
less and the gate wiring is formed by a droplet discharge method.

29. A television set comprising a display device including a wiring formed
by a droplet discharge method and an electrode connected to the wiring,
wherein the electrode has a width of 5 μm or less.

30. A television set comprising:a display device including a thin film
transistor with a gate electrode, a gate insulating film, a semiconductor
region, a source electrode, and a drain electrode; anda gate wiring
connected to the gate electrode,wherein the gate electrode has a width of
5 μm or less and the gate wiring is formed by a droplet discharge
method.

31. A television set according to any one of claims 27 to 30, wherein the
television set is a liquid crystal television or an EL television.

Description:

TECHNICAL FIELD

[0001]The present invention relates to a semiconductor device and a
television set having a semiconductor element formed by a droplet
discharge method typified by an ink-jet method and to a method for
manufacturing the semiconductor device and the television set.

BACKGROUND ART

[0002]In manufacturing of a semiconductor device, consideration is given
to using a droplet discharge method to form a pattern of a thin film or a
wiring used for a semiconductor element with a view to reduction in cost
of equipment and simplification of a process.

[0003]On this occasion, in forming a film pattern in a semiconductor
element, a film pattern is formed by performing a photolithography step
of applying a resist to an entire surface of a substrate, prebaking, and
then irradiating with ultraviolet rays or the like with a mask pattern
therebetween and developing to form a resist pattern, and by etching and
removing a film existing in a portion to be a film pattern (a film formed
of a semiconductor material, an insulating material, or a conductive
material) using the resist pattern as a mask pattern.

[0004]In addition, a technique for forming a film over a semiconductor
wafer by using an apparatus capable of continuously discharging a resist
in a linear shape with a fine diameter from a nozzle in order to improve
a yield of a liquid required for film formation is disclosed in Reference
1 (Reference 1: Japanese Patent Laid-Open No. 2000-188251).

DISCLOSURE OF INVENTION

[0005]However, a droplet of a solution with a small diameter needs to be
discharged to form a semiconductor element having small occupied area by
a droplet discharge method according to the technique disclosed in
Reference 1. When a diameter of a discharge opening is made small for
this reason, a composition of a discharge solution may be attached to an
a discharge opening, dried, and solidified, and a clogged opening or the
like may be caused. Thus, it is difficult to continuously and stably
discharge a certain amount of discharge solution. Consequently, there is
a problem of causing decrease in a throughput or a yield of a
semiconductor device formed with the semiconductor element.

[0006]The present invention is made in view of such problems and, it is an
object of the invention to provide a method for manufacturing a
semiconductor element having a minute structure, and further, a
semiconductor device and a television set having a high throughput or a
high yield at low cost and a manufacturing method thereof.

[0007]One feature of the invention is that a first film pattern is formed
by a droplet discharge method, a photosensitive material is discharged or
applied to the first film pattern, a mask pattern is formed by
irradiating a region where the first film pattern and the photosensitive
material are overlapped with a laser beam and by developing, and a second
film pattern having a desired shape is formed by etching the first film
pattern using the mask pattern as a mask.

[0008]Another feature of the invention is that a first film pattern is
formed by a droplet discharge method, a photosensitive material is
discharged or applied to the first film pattern, a mask pattern is formed
by irradiating a region where the first film pattern and the
photosensitive material are overlapped with a laser beam and by
developing, a second film pattern having a desired shape is formed by
etching the first film pattern using the mask pattern as a mask, and a
third film pattern to be connected to the second film pattern is formed
by a droplet discharge method.

[0009]The photosensitive material is either a negative photosensitive
resin or a positive photosensitive resin.

[0010]The first film pattern is a conductive film, the second film pattern
is a gate electrode, a source electrode, or a drain electrode, and then,
the third film pattern is a wiring.

[0011]The first film pattern is a semiconductor film, and the second film
pattern has a channel formation region, a source region, and a drain
region.

[0012]The first film pattern is an insulating film, and the second film
pattern is an insulating film having an opening.

[0013]Another feature of the invention is that a first film pattern is
formed by discharging a conductive material with a droplet discharge
method, a first photosensitive material is discharged or applied to the
first film pattern, a first mask pattern is formed by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing, a gate electrode
having a desired shape is formed by etching the first film pattern using
the first mask pattern as a mask, an insulating film and a semiconductor
film are formed over the gate electrode, a second photosensitive material
is applied or discharged to the semiconductor film, a second mask pattern
is formed by irradiating the second photosensitive material with a laser
beam and by developing, a semiconductor region having a desired shape is
formed by etching the semiconductor film using the second mask pattern as
a mask, and a source electrode and a drain electrode to be in contact
with the semiconductor region are formed.

[0014]Another feature of the invention is that a first film pattern is
formed by discharging a conductive material by a droplet discharge
method, a first photosensitive material is discharged or applied to the
first film pattern, a first mask pattern is formed by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing, a gate electrode
having a desired shape is formed by etching the first film pattern using
the first mask pattern as a mask, an insulating film and a first
semiconductor film are formed over the gate electrode, a protective film
is formed over the first semiconductor film, a second semiconductor film
is formed over the first semiconductor film and the protective film, a
second photosensitive material is applied or discharged to the second
semiconductor film, a second mask pattern is formed by irradiating the
second photosensitive material with a laser beam and by developing, a
semiconductor region having a desired shape is formed by etching the
first semiconductor film and the second semiconductor film using the
second mask pattern as a mask, and a source electrode and a drain
electrode to be in contact with the semiconductor region are formed.

[0015]Another feature of the invention is that a first film pattern is
formed by discharging a conductive material with a droplet discharge
method, a first photosensitive material is discharged or applied to the
first film pattern, a first mask pattern is formed by irradiating a
region where the first film pattern and the first photosensitive material
are overlapped with a laser beam and by developing, a source electrode
and a drain electrode having a desired shape are formed by etching the
first film pattern using the first mask pattern as a mask, a
semiconductor film is formed over the source electrode and the drain
electrode, a second photosensitive material is applied or discharged to
the semiconductor film, a second mask pattern is formed by irradiating
the second photosensitive material with a laser beam and by developing, a
semiconductor region having a desired shape is formed by etching the
semiconductor film using the second mask pattern as a mask, and an
insulating film and a gate electrode are formed over the semiconductor
region.

[0016]The invention is a method for manufacturing a television set,
characterized in that a first film pattern is formed by discharging a
conductive material with a droplet discharge method, a first
photosensitive material is discharged or applied to the first film
pattern, a first mask pattern is formed by irradiating a region where the
first film pattern and the first photosensitive material are overlapped
with a laser beam and by developing, a gate electrode having a desired
shape is formed by etching the first film pattern using the first mask
pattern as a mask, an insulating film and a semiconductor film are formed
over the gate electrode, a second photosensitive material is applied or
discharged to the semiconductor film, a second mask pattern is formed by
irradiating the second photosensitive material with a laser beam and by
developing, a semiconductor region having a desired shape is formed by
etching the semiconductor film using the second mask pattern as a mask, a
source electrode and a drain electrode to be in contact with the
semiconductor region are formed, and a pixel electrode to be connected to
the drain electrode is formed.

[0017]The invention is a method for manufacturing a television set,
characterized in that a first film pattern is formed by discharging a
conductive material with a droplet discharge method, a first
photosensitive material is discharged or applied to the first film
pattern, a first mask pattern is formed by irradiating a region where the
first film pattern and the first photosensitive material are overlapped
with a laser beam and by developing, a gate electrode having a desired
shape is formed by etching the first film pattern using the first mask
pattern as a mask, an insulating film and a first semiconductor film are
formed over the gate electrode, a protective film is formed over the
first semiconductor film, a second semiconductor film is formed over the
first semiconductor film and the protective film, a second photosensitive
material is applied or discharged to the second semiconductor film, a
second mask pattern is formed by irradiating the second photosensitive
material with a laser beam and by developing, a semiconductor region
having a desired shape is formed by etching the first semiconductor film
and the second semiconductor film using the second mask pattern as a
mask, a source electrode and a drain electrode to be in contact with the
semiconductor region are formed, and a pixel electrode to be connected to
the drain electrode is formed.

[0018]The invention is a method for manufacturing a television set,
characterized in that a first film pattern is formed by discharging a
conductive material with a droplet discharge method, a first
photosensitive material is discharged or applied to the first film
pattern, a first mask pattern is formed by irradiating a region where the
first film pattern and the first photosensitive material are overlapped
with a laser beam and by developing, a source electrode and a drain
electrode having a desired shape are formed by etching the first film
pattern using the first mask pattern as a mask, a semiconductor film is
formed over the source electrode and the drain electrode, a second
photosensitive material is applied or discharged to the semiconductor
film, a second mask pattern is formed by irradiating the second
photosensitive material with a laser beam and by developing, a
semiconductor region having a desired shape is formed by etching the
semiconductor film using the second mask pattern as a mask, an insulating
film and a gate electrode are formed over the semiconductor region, and a
pixel electrode to be connected to the drain electrode is formed.

[0019]The first photosensitive material and the second photosensitive
material are negative photosensitive resins.

[0020]The first photosensitive material and the second photosensitive
material are positive photosensitive resins.

[0021]One of the first photosensitive material and the second
photosensitive material is a negative photosensitive resin, and the other
thereof is a positive photosensitive resin.

[0022]In the invention, the laser beam has any wavelength of from
ultraviolet light to infrared light.

[0023]In addition, the invention is a semiconductor device having a wiring
formed by a droplet discharge method and an electrode connected to the
wiring, characterized in that the electrode has widths of 5 μm or
less.

[0024]The invention is a semiconductor device having a thin film
transistor provided with a gate electrode, a gate insulating film, a
semiconductor region, a source electrode, and a drain electrode and a
gate wiring connected to the gate electrode, characterized in that the
gate electrode has widths of 5 μm or less and the gate wiring is
formed by a droplet discharge method.

[0025]The invention is a television set provided with a display device
having a wiring formed by a droplet discharge method and an electrode
connected to the wiring, in which the electrode has widths of 5 μm or
less.

[0026]The invention is a television set provided with a display device
having a thin film transistor with a gate electrode, a gate insulating
film, a semiconductor region, a source electrode, and a drain electrode
and a gate wiring connected to the gate electrode, in which the gate
electrode has widths of 5 μm or less and the gate wiring is formed by
a droplet discharge method.

[0027]As a typical example of the television set, a liquid crystal
television set or an EL television set can be given.

[0028]As a semiconductor element included in a pixel, a TFT, a field
effect transistor (FET), a MOS transistor, a bipolar transistor, an
organic semiconductor transistor, a MIM element, a memory element, a
diode, a photoelectric conversion element, a capacitor element, a
resistor element, or the like can be given.

[0029]In the invention, a display device that is one of typical examples
of a semiconductor device means a device with the use of a display
element, that is, an image display device. Further, a display device
includes: a module having a display panel attached with a connector such
as an FPC (Flexible Printed Circuit), a TAB (Tape Automated Bonding)
tape, or a TCP (Tape Carrier Package); a module having a TAB tape or a
TCP provided with a printed wiring board at the end thereof; and a module
having a display element directly mounted with an IC (Integrated Circuit)
or a CPU by a COG (Chip On Glass) method.

[0030]A minute mask pattern can be formed without using a photomask by
performing etching with a mask pattern formed by directly irradiating
with a laser beam as in the invention. Thus, microfabrication of a film
pattern formed by a droplet discharge method can be performed, and a
semiconductor element with a minute structure can be formed.

[0031]When a droplet discharge method is employed in forming a film
pattern, a droplet can be discharged to an arbitrary position by changing
a relative position of a nozzle that is a discharge opening of a droplet
including a film material thereofs and a substrate. In addition, a
thickness and a width of a pattern to be formed can be adjusted depending
on a nozzle diameter, the discharge amount of droplets, and a relative
relationship between movement speed of a nozzle and that of a substrate
to be provided with a discharged droplet. Accordingly, a film pattern can
be formed in a desired portion with high accuracy by discharging even
over a large area semiconductor element substrate having a side of 1 m to
2 m or more. Since light exposure and development process using a
photomask can be omitted, simplification of a process and reduction in
cost can be achieved.

[0032]Further, a semiconductor device such as a highly integrated circuit
or a display device having a high aperture ratio, or a television set can
be manufactured at low cost with high throughput and yield by using a
semiconductor element with a minute structure.

BRIEF DESCRIPTION OF DRAWINGS

[0033]FIGS. 1A to 1E are perspective views showing a step of forming a
film pattern according to the present invention.

[0034]FIG. 2 is a surface view showing a step of forming a film pattern
according to the present invention.

[0035]FIGS. 3A to 3F are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0036]FIGS. 4A to 4E are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0037]FIGS. 5A to 5G are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0038]FIGS. 6A to 6E are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0039]FIGS. 7A to 7E are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0040]FIG. 8 is a schematic diagram showing a laser direct drawing
apparatus according to the present invention.

[0041]FIGS. 9A to 9C are top views showing a mounting method of a driver
circuit of a display device according to the present invention.

[0042]FIGS. 10A to 10D are cross-sectional views showing a mounting method
of a driver circuit of a display device according to the present
invention.

[0043]FIG. 11 is a block diagram showing a structure of an electronic
device.

[0044]FIG. 12 shows an example of an electronic device.

[0045]FIGS. 13A and 13B show an example of an electronic device.

[0046]FIG. 14 shows a circuit structure in the case of forming a scanning
line side driver circuit with TFTs in a liquid crystal display panel
according to the present invention.

[0047]FIG. 15 shows a circuit structure in the case of forming a scanning
line side driver circuit with TFTs in a liquid crystal display panel
according to the present invention (shift register circuit).

[0048]FIG. 16 shows a circuit structure in the case of forming a scanning
line side driver circuit with TFTs in a liquid crystal display panel
according to the present invention (buffer circuit).

[0049]FIGS. 17A to 17G are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0050]FIGS. 18A to 18D are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0051]FIG. 19 is a top view showing a manufacturing step of a
semiconductor device according to the present invention.

[0052]FIG. 20 is a top view showing a manufacturing step of a
semiconductor device according to the present invention.

[0053]FIG. 21 is a top view showing a manufacturing step of a
semiconductor device according to the present invention.

[0054]FIGS. 22A and 22B show a liquid crystal drop method which can be
applied to the present invention.

[0055]FIG. 23 shows a structure of a liquid crystal display module
according to the present invention.

[0056]FIG. 24 shows a structure of a droplet discharge apparatus which can
be applied to the present invention.

[0057]FIGS. 25A and 25B are surface views showing a mask pattern according
to the present invention.

[0058]FIGS. 26A to 26D show modes of a light emitting element which can be
applied to the present invention.

[0059]FIGS. 27A to 27F are equivalent circuit diagrams showing a structure
of a pixel which can be applied to a light-emitting display panel of the
present invention.

[0060]FIGS. 28A to 28C are a top view and cross-sectional views showing a
structure of a light emitting display panel of the present invention.

[0061]FIGS. 29A to 29E are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0062]FIGS. 30A to 30D are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0063]FIGS. 31A and 31B are cross-sectional views showing a manufacturing
step of a semiconductor device according to the present invention.

[0064]FIG. 32 is a top view showing a manufacturing step of a
semiconductor device according to the present invention.

[0065]FIG. 33 is a top view showing a manufacturing step of a
semiconductor device according to the present invention.

[0066]FIG. 34 is a top view showing a manufacturing step of a
semiconductor device according to the present invention.

[0067]FIGS. 35A to 35C show a structure of a light emitting display module
according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0068]Hereinafter, the best mode for carrying out the invention is
described with reference to drawings. The present invention is not
limited to the following description. As is easily known to a person
skilled in the art, the mode and the detail of the invention can be
variously changed without departing from the purpose and the scope of the
present invention. The present invention is not interpreted while
limiting to the following description of the embodiment mode. In
addition, the same reference numeral is given to a common portion in each
drawing, and detailed description is omitted.

Embodiment Mode 1

[0069]A step of forming a narrow wiring using a mask pattern formed by
being irradiated with a laser beam (hereinafter, also referred to as
laser light) is described in this embodiment mode with reference to FIGS.
1A to 1E and FIG. 2.

[0070]FIG. 2 is a plan view of a substrate 101 in which a pixel 110 is
arranged in a matrix. A third conductive layer 107 which functions as a
gate wiring of a semiconductor element to be formed later is shown in
solid line over the substrate 101. In addition, a source wiring, a
semiconductor region, a source electrode, a drain electrode, a pixel
electrode, and the like of a semiconductor element to be formed later are
shown in dashed line.

[0071]FIGS. 1A to 1E are front perspective views of the substrate in FIG.
2 taken along a line A-B. A manufacturing process of the invention is
described with reference to FIGS. 1A to 1E.

[0072]A first conductive layer 102 is formed over the substrate 101 by a
droplet discharge method as shown in FIG. 1A.

[0073]As the substrate 101, a glass substrate, a quartz substrate, a
substrate made of an insulating material of ceramic or the like such as
alumina, a heat-resistant plastic substrate which can withstand a
processing temperature of post-process, a silicon wafer, a metal plate,
or the like can be used. In addition, a large area substrate of 320
mm×400 mm, 370 mm×470 mm, 550 mm×650 mm, 600
mm×720 mm, 680 mm×880 mm, 1000 mm×1200 mm, 1100
mm×1250 mm, 1150 mm×1300 mm, or the like can be used as the
substrate 101.

[0074]A conductor dissolved or dispersed in a solvent is used as a
composition to be discharged from a discharge opening as a material of
the first conductive layer. A particle of a metal such as Ag, Au, Cu, Ni,
Pt, Pd, Ir, Rh, W, Al, Ta, Mo, Cd, Zn, Fe, Ti, Si, Ge, Zr, or Ba, a
dispersant nanoparticle thereof, or a fine particle of silver halide can
be used as the conductor. Alternatively, ITO (indium tin oxide), ITO
containing silicon oxide as a composition, organic indium, organic tin,
zinc oxide (ZnO), titanium nitride (TiN), which is typically used as a
transparent conductive film or the like, can be used. In addition, the
first conductive layer can be formed by laminating a conductive layer
made of the material.

[0075]As for the composition to be discharged from a discharge opening, it
is preferable to use any material of gold, silver, and copper, which is
dissolved or dispersed in a solvent, taking a specific resistance value
into consideration. It is more preferable to use silver or copper which
is low resistant and inexpensive. When silver or copper is used, a
barrier film may be additionally provided as a measure for an impurity.
As for the solvent, an organic solvent of esters such as butyl acetate
and ethyl acetate, alcohols such as isopropyl alcohol and ethyl alcohol,
methyl ethyl ketone, or acetone or the like may be used.

[0076]Here, an insulating or conductive material containing nitrogen such
as silicon nitride, silicon oxynitride, aluminum nitride, titanium
nitride, or tantalum nitride (TaN) is preferably used as the barrier film
in the case of using copper as a wiring, and the material may be formed
by a droplet discharge method.

[0077]The viscosity of the composition used for a droplet discharge method
is preferably from 5 mPas to 20 mPas. This is because the composition can
be prevented from drying or the composition can be smoothly discharged
from a discharge opening. The surface tension of the composition is
preferably 40 mN/m or less. Note that the viscosity of the composition
and the like may be appropriately adjusted in accordance with a solvent
to be used and intended use. For example, the viscosity of a composition
in which ITO, ITO containing silicon oxide as a composition, organic
indium, or organic tin is dissolved or dispersed in the solvent may be
from 5 mPas to 20 mPas, the viscosity of a composition in which silver is
dissolved or dispersed in the solvent may be from 5 mPas to 20 mPas, and
the viscosity of a composition in which gold is dissolved or dispersed in
the solvent may be from 10 mPas to 20 mPas.

[0078]The diameter of a particle of the conductor is preferably made as
small as possible for the purpose of preventing clogged nozzles and
manufacturing a high-definition pattern, although it depends on the
diameter of each nozzle, a desired shape of a pattern, and the like.
Preferably, the diameter of the particle of the conductive material is
0.1 μm or less. The composition is formed by a known method such as an
electrolyzing method, an atomizing method, a wet reducing method, or the
like, and the particle size thereof is typically about from 0.5 μm to
10 μm. However, when a gas evaporation method is employed, a
nanomolecule protected with a dispersant is minute, about 7 nm. When each
surface of nanoparticles is covered with a coating, the nanoparticles do
not cohere in the solvent and are uniformly dispersed in the solvent at a
room temperature, and show a property similar to that of liquid.
Accordingly, it is preferable to use a coating.

[0079]The step of discharging a composition may be performed under reduced
pressure. This is because the solvent of the composition is evaporated
during a period from discharging the composition until the composition
lands on an object to be treated, and thus, later steps of drying and
baking the composition can both be omitted or shortened. After
discharging the solution, either or both steps of drying and baking
is/are performed at normal pressure or under reduced pressure depending
on the kind of solution by laser light irradiation, rapid thermal
annealing, a heating furnace, or the like. Each step of drying and baking
is a step of heat treatment. For example, drying is performed for three
minutes at 100° C. and baking is performed for from 15 minutes to
120 minutes at a temperature of from 200° C. to 350° C.,
each of which has a different purpose, temperature, and period. The
substrate may be heated to favorably perform the steps of drying and
baking. The temperature of heating the substrate at the time depends on a
material of the substrate or the like, but it is set from 100° C.
to 800° C. (preferably, from 200° C. to 350° C.).
According to the steps, fusion and welding are accelerated by evaporating
the solvent in the solution or chemically removing the dispersant and
hardening and shrinking a peripheral resin. The steps are performed in an
oxygen atmosphere, a nitrogen atmosphere, or an atmospheric air. The
steps are preferably performed in an oxygen atmosphere where the solvent
in which a metal element is dissolved or dispersed is easily removed.

[0080]A continuous wave or pulsed wave gas laser or solid laser may be
used for laser light irradiation. An excimer laser, a YAG laser, and the
like can be given as a gas laser, and a laser using a crystal of YAG,
YVO4, or the like which is doped with Cr, Nd, or the like can be
given as a solid laser. Note that it is preferable to use a continuous
wave laser in relation to the absorptance of laser light. Moreover, a
so-called hybrid laser irradiation method which combines a pulsed wave
and a continuous wave may be used. However, the heat treatment by laser
light irradiation is preferably instantaneously performed within several
microseconds to several tens of seconds, depending on heat resistance of
the substrate. Rapid thermal annealing (RTA) is carried out by raising
the temperature rapidly and heating for several microseconds to several
minutes using an infrared lamp or a halogen lamp emitting light of from
ultraviolet to infrared in an inert gas atmosphere. Since the treatment
is performed instantaneously, the treatment has the advantage that only a
thin film on a top surface can be substantially heated and a lower layer
film is not affected.

[0081]Here, a first conductive layer having thicknesses of from 600 nm to
800 nm is formed by selectively discharging a composition containing Ag
(hereinafter, referred to as Ag paste) and appropriately drying and
baking with laser beam irradiation or heat treatment as described above.
When the baking is performed in an O2 atmosphere, an organic
material such as a binder (thermosetting resin) contained in Ag paste is
decomposed and an Ag film which hardly contains an organic material can
be obtained. In addition, a film surface can be made smooth. Since a
solvent in the paste is evaporated by discharging the Ag paste under
reduced pressure, later heat treatment can be omitted or heat treatment
time can be shortened.

[0082]In this embodiment mode, a conductive layer which includes silver as
a main component is formed as a first film pattern. Note that the
conductive layer is formed so that conductive fine particles
three-dimensionally and irregularly overlap each other. That is, the
conductive film is composed of three-dimensional cohering particles.
Therefore, a surface of the conductive layer is slightly uneven.
Additionally, the particles are melted to form a cluster, depending on a
temperature and time of heating the conductive layer. The cluster is
increased in size depending on a temperature and time of heating the
conductive layer. In this case, a surface of the conductive layer becomes
uneven markedly. Note that a region where the particle is melted may have
a polycrystalline structure in some cases.

[0083]In this embodiment mode, the first conductive layer is described;
however, a semiconductor layer or an insulating layer can be
appropriately applied in place of the conductive layer.

[0084]Subsequently, a photosensitive resin 103 is discharged or applied to
the first conductive layer 102 as shown in FIG. 1B. A negative
photosensitive resin or positive photosensitive resin which is
photosensitive to from ultraviolet light to infrared light is used as the
photosensitive resin. A photosensitive resin material such as an epoxy
resin, an acrylic resin, a phenol resin, a novolac resin, a melamine
resin, or a urethane resin is used as the photosensitive resin.
Alternatively, a photosensitive organic material such as
benzocyclobutene, parylene, flare, or polyimide can be used. Further, a
photosensitive resin having a novolac resin and a naphthoquinone diazide
compound which is a photosensitive agent can be given as a typical
positive photosensitive resin, and a photosensitive resin having a base
resin and diphenylsilanediol, an acid generation agent, and the like can
be given as a typical negative photosensitive resin. In this embodiment
mode, a negative photosensitive resin is used.

[0085]Subsequently, the photosensitive resin 103 is irradiated with a
laser beam 104 by using a laser beam direct drawing apparatus. In this
embodiment mode, laser beam irradiation is performed with the substrate
moved as indicated by an arrow in the drawing.

[0086]Here, the laser beam direct drawing apparatus is described with
reference to FIG. 8. As shown in FIG. 8, a laser beam direct drawing
apparatus 1001 includes: a personal computer (hereinafter referred to as
a PC) 1002 for conducting various types of control in irradiating with a
laser beam; a laser oscillator 1003 for outputting a laser beam; a power
source 1004 of the laser oscillator 1003; an optical system (ND filter)
1005 for attenuating the laser beam; an acousto-optic modulator (AOM)
1006 for modulating intensity of the laser beam; an optical system 1007
having a lens for enlarging or reducing a cross section of the laser
beam, a mirror for changing a light path, and the like; a substrate
movement mechanism 1009 having an X stage and a Y stage; a D/A converter
1010 for converting control data outputted from the PC into
digital/analog; a driver 1011 for controlling the acousto-optic modulator
(AOM) 1006 in accordance with an analog voltage outputted from the D/A
converter, and a driver 1012 for outputting a driving signal for driving
the substrate movement mechanism 1009.

[0087]A laser oscillator that can oscillate ultraviolet light, visible
light, or infrared light can be used as the laser oscillator 1003. An
excimer laser oscillator of KrF, ArF, XeCl, Xe, or the like, a gas laser
oscillator of He, He--Cd, Ar, He--Ne, HF, or the like, a solid laser
oscillator using crystal such as YAG, YVO4, YLF, or YAlO3 doped
with Cr, Nd, Er, Ho, Ce, Co, Ti, or Tm, a semiconductor laser oscillator
of GAN, GaAs, GaAlAs, InGaAsP, or the like can be used as the laser
oscillator. Note that it is preferable to apply any of second to fifth
harmonics of a fundamental wave to the solid laser oscillator.

[0088]Subsequently, a method for exposing a photosensitive material to
light with the use of the laser beam direct drawing apparatus is
described. When a substrate 1008 is mounted on the substrate movement
mechanism 1009, the PC 1002 detects a position of a marker marked on the
substrate with a camera which is not shown in the diagram. Next, the PC
1002 generates movement data for moving the substrate movement mechanism
1009 based on position data of the detected marker and preliminarily
inputted drawing pattern data. Thereafter, the PC 1002 controls the
amount of output light from the acousto-optic modulator (AOM) 1006
through the driver 1011. Accordingly, after a laser beam outputted from
the laser oscillator 1003 is attenuated by the optical system (ND filter)
1005, the amount of light is controlled by the acousto-optic modulator
(AOM) 1006 to be the predetermined amount. On the other hand, a light
path and a beam shape of the laser beam outputted from the acousto-optic
modulator (AOM) 1006 is changed by the optical system 1007 and the laser
beam is collected by a lens. Thereafter, a photosensitive material
applied to the substrate is irradiated with the beam and is exposed to
light. At this time, the movement of the substrate movement mechanism
1009 is controlled in an X direction and a Y direction in accordance with
the movement data generated by the PC 1002. Consequently, a predetermined
portion is irradiated with the laser beam, and light exposure of the
photosensitive material is performed.

[0089]Accordingly, a mask pattern 105 is formed in a region irradiated
with the laser beam as shown in FIG. 1C. Since a negative photosensitive
resin is used here, the region irradiated with the laser beam becomes the
mask pattern. A width of a mask pattern corresponds to a width of the
laser beam when a laser beam scans once. Thus, a laser beam having a
shorter wavelength is emitted to form a mask pattern with a minuter
width.

[0090]Here, the substrate is moved and selectively irradiated with a laser
beam; however, the invention is not limited thereto. The laser beam can
be emitted by making the laser beam scan in an X-Y axis direction. In
this case, a polygon mirror or a galvanometer mirror is preferably used
in the optical system 1007.

[0091]Subsequently, the first conductive layer 102 is etched by a known
method such as dry etching or wet etching using the mask pattern 105 as a
mask. As a result, a second conductive layer 106 having a narrow width
can be formed as shown in FIG. 1D. Note that the second conductive layer
106 can be used as a gate electrode of a later semiconductor element.

[0092]Then, a third conductive layer 107 is discharged by a droplet
discharge method as shown in FIG. 1E. The third conductive layer 107 is
formed to partially overlap the second conductive layer 106. Thereafter,
either or both steps of drying and baking is/are performed on the third
conductive layer.

[0093]According to the above-described steps, a film pattern with a minute
width and a gate wiring having the same can be formed.

Embodiment Mode 2

[0094]A method for manufacturing a semiconductor element is described
hereinafter. The following embodiment mode is described using a TFT as a
semiconductor element; however, the invention is not limited thereto. An
organic semiconductor transistor, a diode, a MIM element, a memory
element, a diode, a photoelectric conversion element, a capacitor
element, a resistor element, or the like can be used.

[0095]In this embodiment mode, a step of manufacturing a channel etch type
TFT that is one of an inversely staggered type (bottom gate type) TFT as
a semiconductor element is described with reference to FIGS. 3A to 3F.

[0096]As shown in FIG. 3A, a first conductive layer 302 is formed over a
substrate 101. A droplet discharge method is employed as a formation
method of the first conductive layer 302. In addition, the same
conductive material as the first conductive layer 102 described in
Embodiment Mode 1 can be appropriately used as a material of the first
conductive layer.

[0097]Before the first conductive layer 302 is formed, a base layer formed
with a metal material such as Ti (titanium), W (tungsten), Cr (chromium),
Ta (tantalum), Ni (nickel), or Mo (molybdenum) or oxide thereof by a
sputtering method or an evaporation method is preferably formed over the
surface of the substrate 301. The base layer may be formed to be from
0.01 nm to 10 nm in thickness, but it does not necessarily have a layer
structure since it may be formed extremely thin. Note that the base layer
is provided to form the first conductive layer with good adhesion, and it
may be omitted when sufficient adhesion can be obtained. In the case of
using a conductive film as the base layer, the base layer can be etched
using a first mask pattern together with the first conductive layer.

[0098]Subsequently, a first photosensitive resin 103 is discharged or
applied to the first conductive layer 302. In this embodiment mode, a
negative photosensitive resin is discharged to the first conductive layer
by a droplet discharge method. Then, the photosensitive resin is partly
irradiated with a laser beam 104 to expose to light and to develop,
thereby forming a first mask pattern 311 shown in FIG. 3B.

[0099]Next, the first conductive layer 302 is etched using the first mask
pattern 311 as a mask to form a gate electrode 321 as shown in FIG. 3C.
Here, the first conductive layer is etched by dry etching. Thereafter,
the first mask pattern is removed by treatment with the use of a removing
solution, ashing treatment with the use of oxygen, or the like.

[0100]Subsequently, a first insulating film 322, a first semiconductor
film 323, and a second semiconductor film 324 are sequentially formed
over the substrate and the gate electrode. The first insulating film 322,
the first semiconductor film 323, and the second semiconductor film 324
each serve as a gate insulating film, a channel formation region,
source/drain region of a TFT to be formed later, respectively.

[0101]The first insulating film 322 is formed by a thin film formation
method such as a plasma CVD method or a sputtering method to be a single
layer of silicon nitride, silicon oxide, or another insulating film
containing silicon or to have a laminated structure thereof. In addition,
the first insulating film preferably has a laminated structure of a
silicon nitride film (silicon nitride oxide film), a silicon oxide film,
and a silicon nitride film (silicon nitride oxide film) from a side in
contact with the gate electrode. Since the gate electrode is in contact
with the silicon nitride film in this structure, deterioration due to
oxidation can be prevented.

[0102]The first semiconductor film 323 is formed by using a film having
any state of semiconductor selected from an amorphous semiconductor, a
semi-amorphous semiconductor in which an amorphous state and a
crystalline state are mixed (also referred to as a SAS), a
microcrystalline semiconductor in which a crystal grain of from 0.5 nm to
20 nm can be observed within an amorphous semiconductor, and a
crystalline semiconductor. Specifically, a microcrystalline state in
which a crystal grain of from 0.5 nm to 20 nm can be observed is referred
to as microcrystal (μc). In any case, a semiconductor film mainly
containing silicon, silicon germanium (SiGe), or the like with
thicknesses of from 10 nm to 60 nm can be used.

[0103]The SAS means a semiconductor having an intermediate structure
between an amorphous structure and a crystalline structure (including a
single crystal and a polycrystal) and having a third state which is
stable in terms of free energy. The SAS includes a crystalline region
having short-range order and lattice distortion. A crystalline region of
from 0.5 nm to 20 nm can be observed in at least a part of a region in
the film. When silicon is contained as the main component, a Raman
spectrum is shifted to a lower frequency side than 520 cm-1. A
diffraction peak of (111) or (220) to be caused by a crystal lattice of
silicon is observed in X-ray diffraction. In addition, the SAS contains
hydrogen or halogen of at least 1 atomic % or more to terminate a
dangling bond.

[0104]The SAS can be obtained by performing glow discharge decomposition
on a silicide gas. SiH4 is given as a typical silicide gas. In
addition, Si2H6, SiH2Cl2, SiHCl3, SiCl4,
SiF4, or the like can also be used as the silicide gas. The silicide
gas may be diluted with hydrogen or fluorine, or hydrogen or fluorine and
one or more rare gas elements of helium, argon, krypton, and neon,
thereby making formation of the SAS easy. At this time, it is preferable
to dilute the silicide gas so that a dilution ratio ranges from 10 times
to 1000 times. Alternatively, the SAS can be formed by using
Si2H6 and GeF4 and using a method for diluting with a
helium gas. Formation of a film by glow discharge decomposition is
preferably performed under reduced pressure and may be performed with
pressures in the range of approximately from 0.1 Pa to 133 Pa.
High-frequency powers of from 1 MHz to 120 MHz, preferably, from 13 MHz
to 60 MHz may be supplied to perform a glow discharge. A substrate
heating temperature is preferably 300° C. or less, and a
recommended substrate heating temperature is from 100° C. to
250° C.

[0105]The crystalline semiconductor film can be formed by crystallizing an
amorphous semiconductor film by heating or laser irradiation.
Alternatively, the crystalline semiconductor film may be directly formed.
In this case, the crystalline semiconductor film can be directly formed
by using a fluorine-based gas such as GeF4 or F2 and a
silane-based gas such as SiH4 or Si2H6 and utilizing heat
or plasma.

[0106]The second semiconductor film 324 is conductive, and an element
belonging to Group 15, typically, phosphorus or arsenic is added in the
case of forming an n-channel TFT. An element belonging to Group 13,
typically, boron is added in the case of forming a p-channel TFT. The
second semiconductor film is formed by a plasma CVD method with the use
of a silicide gas added with a gas including an element belonging to
Group 13 or 15 such as boron, phosphorus, or arsenic. After a
semiconductor film is formed, a solution including an element belonging
to Group 13 or 15 is applied to the semiconductor film and is irradiated
with a laser beam; thus, the second semiconductor film which is
conductive can be formed. As the laser beam, a laser beam emitted from a
known pulsed wave laser or continuous wave laser is appropriately used.

[0107]Subsequently, a second photosensitive resin 331 is discharged or
applied to the second semiconductor film 324 as shown in FIG. 3D. Here, a
negative photosensitive resin is discharged by a droplet discharge method
to form the second photosensitive resin 331.

[0108]Next, the second photosensitive resin 331 is irradiated with a laser
beam 332 and is developed to form second mask patterns 341 and 342 shown
in FIG. 3E. In this embodiment mode, a negative resist is used as the
second photosensitive resin; therefore, the second mask patterns 341 and
342 are formed in a region irradiated with the laser beam 332.

[0109]Then, the second semiconductor film 324 is etched by using the
second mask patterns 341 and 342 to form first semiconductor regions
(source/drain regions) 351 and 352. Thereafter, the second mask patterns
are removed.

[0110]According to similar steps, a third photosensitive resin is
discharged or applied, irradiated with a laser beam, and developed to
form a third mask pattern. The first semiconductor layer 323 is etched by
using the third mask pattern to form a second semiconductor region 353.

[0111]A chlorine-based gas typified by Cl2, BCl3, SiCl4,
CCl4, or the like, a fluorine-based gas typified by CF4,
SF6, NF3, CHF3, or the like, or O2 can be used as an
etching gas for the first semiconductor film and the second semiconductor
film.

[0112]Then, source/drain electrodes 354 and 355 are formed over the first
semiconductor regions 351 and 352 by discharging a conductive material
with a droplet discharge method. A similar material to that used for the
first conductive layer 302, which is dissolved or dispersed in a solvent,
can be used as the conductive material. Here, Ag paste is selectively
discharged and laser beam irradiation or drying and baking by heat
treatment is/are appropriately performed as described above. Accordingly,
each electrode having thicknesses of from 600 nm to 800 nm is formed.

[0113]Alternatively, a conductive film is preliminarily formed by a
sputtering method or the like, and a photosensitive material is formed by
a droplet discharge method. Thereafter, the electrodes may be formed by
irradiating the photosensitive material with laser light to form a mask
pattern and by etching. In this case, a positive photosensitive material
is used.

[0114]Subsequently, a passivation film is preferably formed over the
source/drain electrodes 354 and 355. The passivation film can be formed
by a thin film formation method such as a plasma CVD method or a
sputtering method with the use of silicon nitride, silicon oxide, silicon
nitride oxide, silicon oxynitride, aluminum oxynitride, aluminum oxide,
diamond like carbon (DLC), carbon nitride (CN), or another insulating
material.

[0115]According to the above described steps, a channel etch type TFT can
be manufactured.

Embodiment Mode 3

[0116]A step of manufacturing a channel protective type (channel stopper
type) TFT is described in this embodiment mode with reference to FIGS. 4A
to 4E.

[0117]As in Embodiment Mode 2, after performing steps shown in FIGS. 4A
and 4B, a gate electrode 321, a first insulating film 322, and a first
semiconductor film 323 are formed over a substrate 101 as shown in FIG.
4C.

[0118]Subsequently, a protective film 401 is formed in a region over the
first semiconductor film 323, which overlaps the gate electrode 321. The
protective film is preferably formed by using a heat resistant high
molecular weight material. It is preferable to use a high molecular
weight material which has an aromatic ring or a heterocyclic ring as a
main chain, has few aliphatic portions, and includes high polar
heteroatom groups. As a typical example of such a high molecular weight
material, polyimide, polybenzimidazole, or the like can be given. In the
case of using polyimide, a composition containing polyimide is discharged
from a nozzle to the first semiconductor film 323, and then, baked at
200° C. for 30 minutes to form the protective film.

[0119]Then, a second semiconductor film (conductive semiconductor film)
324 is formed as in Embodiment Mode 2. A second photosensitive resin 331
is formed as in Embodiment Mode 2. The second photosensitive resin is
irradiated with a laser beam 332 and is developed to form second mask
patterns 411 and 412 shown in FIG. 4D.

[0120]With the use of the second mask patterns 411 and 412, the second
semiconductor film is etched to form first semiconductor regions
(source/drain regions) 413 and 414; in addition, the first semiconductor
film is etched to form a second semiconductor region (channel formation
region) 415. At this time, a region of the first semiconductor film
overlapping the gate electrode is not etched since the protective film
401 is formed over the first semiconductor film.

[0121]Subsequently, source/drain electrodes 354 and 355 are formed as
shown in FIG. 4E.

[0122]According to the above-described steps, a channel protective type
TFT can be formed. Since the protective film 401 functions as a channel
protective film, the first semiconductor film to be a channel region can
be prevented from being damaged due to overetching or the like in etching
the semiconductor film added with impurities. This makes it possible to
obtain a TFT having higher mobility with a stable characteristic.

Embodiment Mode 4

[0123]A step of manufacturing a staggered TFT is described in this
embodiment mode with reference to FIGS. 5A to 5G.

[0124]A first conductive layer 302 is formed over a substrate 101 as shown
in FIG. 5A. Next, a first photosensitive resin 501 is applied or
discharged to the first conductive layer. Here, a positive photosensitive
resin is used as the first photosensitive resin. Then, the first
photosensitive resin is irradiated with a laser beam 104. Here, a region
to be a channel formation region later is irradiated with the laser beam
104. Thereafter, development is performed to form first mask patterns 511
and 512 as shown in FIG. 5B.

[0125]The first conductive layer 302 is etched by using the first mask
patterns 511 and 512 as a mask to form source/drain electrodes 513 and
514. Thereafter, the first mask patterns are removed.

[0126]Subsequently, a first semiconductor film is formed and a second
photosensitive resin is applied or discharged to the first semiconductor
film and is then irradiated with a laser beam and developed to form
second mask patterns 521 and 522. The first semiconductor film is etched
by using the second mask patterns as a mask to form first semiconductor
regions 523 and 524 (source/drain regions). Here, the first semiconductor
film is a conductive semiconductor film and can be formed by using a
similar material to that of the second semiconductor film 324 described
in Embodiment Mode 2. In addition, a positive photosensitive resin is
used as the second photosensitive resin (FIG. 5C). Thereafter, the second
mask patterns are removed.

[0127]A second semiconductor film is formed and a third photosensitive
resin is applied or discharged to the second semiconductor film and is
then irradiated with a laser beam and developed to form a third mask
pattern 531. The second semiconductor film is etched by using the third
mask pattern as a mask to form a second semiconductor region 532. Here,
the second semiconductor film can be formed by using a similar material
to that of the first semiconductor film 323 described in Embodiment Mode
2. A negative photosensitive resin is used as the third photosensitive
resin (FIG. 5D). Then, the third mask pattern is removed.

[0128]Subsequently, a first insulating film 541 is formed as shown in FIG.
5E. The first insulating film can be formed by using a similar material
to that of the first insulating film 541 described in Embodiment Mode 2.
A second conductive film is discharged between the first semiconductor
regions (source/drain regions). A fourth photosensitive resin is applied
or discharged thereto and is then irradiated with a laser beam and
developed to form a fourth mask pattern. The second conductive layer is
etched by using the fourth mask pattern as a mask to form a gate
electrode 542. Here, the second conductive layer can be formed by using a
similar material to that of the first conductive layer 302. A negative
photosensitive resin is used as the fourth photosensitive resin. Then,
the fourth mask pattern is removed.

[0129]Subsequently, a fifth photosensitive resin 543 is entirely applied
over the substrate, and a region where a contact hole is to be formed
later is irradiated with a laser beam 544 and developed to form a fifth
mask pattern 551 as shown in FIG. 5F. The first insulating film is etched
by using the fifth mask pattern as a mask to expose the source/drain
regions 513 and 514 and to form a gate insulating film 552. Here, a
positive photosensitive resin is used as the fifth photosensitive resin.
Then, the fifth mask pattern is removed.

[0130]Subsequently, third conductive layers 561 and 562 are discharged as
shown in FIG. 5G.

[0131]According to the above-described steps, a staggered TFT can be
formed.

Embodiment Mode 5

[0132]A step of manufacturing a TFT having a top gate structure is
described in this embodiment mode with reference to FIGS. 6A to 6E.

[0133]A first insulating film 582 is formed over a substrate 101 as shown
in FIG. 6A. The first insulating film is provided to prevent impurities
from the substrate 101 from entering a TFT to be formed later. A film
such as a silicon oxide film, a silicon nitride film, or a silicon
oxynitride film is formed as the first insulating film by a known method
such as a PVD method or a CVD method. When the substrate 101 is formed by
using such a material that impurities from the substrate 101 do not enter
a TFT, typically, quartz or the like, the first insulating film 582 need
not be formed.

[0134]A semiconductor film 583 is formed over the first insulating film
582, and a first photosensitive resin 584 is applied or discharged to the
semiconductor film. The first photosensitive resin is irradiated with a
laser beam 104 and developed to form a first mask pattern 585 as shown in
FIG. 6B. The semiconductor film can be formed by using a similar material
to that of the first semiconductor film 323 described in Embodiment Mode
2.

[0135]Subsequently, the semiconductor film is etched by using the first
mask pattern as a mask to form a semiconductor region 586. Thereafter,
the first mask pattern is removed.

[0136]A gate insulating film 587 is formed over the semiconductor region
and a first conductive layer 588 is formed over the gate insulating film
587 as shown in FIG. 6C. The first conductive layer is formed by
appropriately using a similar material and a similar manufacturing step
to those of the first conductive layer 302 described in Embodiment Mode
2. A second photosensitive resin 589 is discharged or applied to the
first conductive layer. A region thereof to be a gate electrode later is
irradiated with a laser beam 590 and developed to form a second mask
pattern 591 as shown in FIG. 6D.

[0137]The first conductive layer 588 is etched by using the first mask
pattern 591 as a mask to form a gate electrode 592. Then, the first mask
pattern is removed.

[0138]The semiconductor region is doped with impurity elements belonging
to Group 13 or 15 by using the gate electrode as a mask to form
source/drain regions 593 and 594 as shown in FIG. 6E. A reference numeral
595 denotes a channel forming region.

[0139]Note that the source/drain regions can be formed by partially
discharging a solution including impurity elements belonging to Group 13
or 15 to the semiconductor region 586 shown in FIG. 6B by a droplet
discharge method and then irradiating the solution with a laser beam. In
this case, the solution including impurity elements belonging to Group 13
or 15 is discharged to a semiconductor region to be source/drain regions
later.

[0140]Subsequently, a second insulating film (interlayer insulating film)
596 is formed According to such steps as described in Embodiment Mode 4,
a mask pattern is formed and the second insulating film and the gate
insulating film are etched to form a contact hole. Thereafter, conductive
films 597 and 598 are formed.

[0141]According to the above-described steps, a TFT having a top gate
structure can be formed.

Embodiment Mode 6

[0142]A method for forming a contact hole different from Embodiment Modes
4 and 5 is described in this embodiment mode with reference to FIGS. 7A
to 7E.

[0143]According to Embodiment Mode 4, a staggered TFT is formed as shown
in FIG. 7A. Here, a substrate 101 is provided with source/drain
electrodes 513 and 514, first semiconductor regions 523 and 524, a second
semiconductor region 532 formed over the first semiconductor regions
between the source/drain electrodes, a first insulating film 541, and a
gate electrode 542.

[0144]A solution which forms a liquid-repellent surface is discharged to a
region where the source/drain electrodes are overlapped with the first
insulating film 541 to form first mask patterns 571 and 572 by a droplet
discharge method as shown in FIG. 7B.

[0145]The first mask patterns are formed by using a solution which forms a
liquid-repellent surface. For example, a silane coupling agent expressed
in a chemical formula Rn--Si--X.sub.(4-n) (n=1, 2, or 3) is used as
an example of a composition of the solution which forms a
liquid-repellent surface. Here, R denotes a substance which contains a
comparatively inert group such as an alkyl group. X is formed with a
hydrolytic group that is bondable by condensation with a hydroxyl group
or absorbed water on the surface of the substrate, such as halogen, a
methoxy group, an ethoxy group, or an acetoxy group.

[0146]In addition, liquid repellency can be further enhanced by using a
fluorine-based silane coupling agent containing a fluoroalkyl group as R
(fluoroalkyl silane (hereinafter, referred to as FAS)), which is given as
a typical example of the silane coupling agent. R of FAS has a structure
expressed by (CF3)(CF2)x(CH2)y (x: an integer in
the range of from 0 to 10, and y: an integer in the range of from 0 to
4). When a plurality of Rs or Xs are combined with Si, the Rs or Xs may
be all the same or different from each other. Heptadecafluoro tetrahydro
decyl triethoxysilane, heptadecafluoro tetrahydro decyl trichlorosilane,
tridecafluoro tetrahydro octyl trichlorosilan, trifluoropropyl
trimethoxysilane, or the like is typically given as FAS.

[0147]A solvent which forms a liquid-repellent surface, for example, a
hydrocarbon-based solvent or tetrahydrofuran such as n-pentane, n-hexane,
n-heptane, n-octane, n-decane, dicyclopentane, benzene, toluene, xylene,
durene, indene, tetrahydronaphthalene, decahydronaphthalene, or squalane
is used as a solvent of the solution which forms a liquid-repellent
surface.

[0148]In addition, a material having a fluorine carbon chain
(fluorine-based resin) can be used as one example of the composition of
the solution which forms a liquid-repellent surface.
Polytetrafluoroethylene (PTFE), perfluoloalkoxy alkane (PFA),
perfluoroethylene-propylene copolymer (PFEP),
ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride
(PVDF), polychlorotrifluoroethylene (PCTFE),
ethylene-chlorotrifluoroethylene copolymer (ECTFE),
polytetra-fluoroethylene-perfluoro dioxole copolymer (TFE/PDD), polyvinyl
fluoride (PVF), or the like can be used as the fluorine-based resin.

[0149]An organic material which does not form a liquid-repellent surface
(that is, which forms a lyophilic surface) may be used for the mask
pattern. In this case, the organic material may be treated with CF4
plasma or the like to form a liquid-repellent surface. For example, a
material in which a water soluble resin such as polyvinyl alcohol (PVA)
is mixed into a solvent such as H2O may be used. Further, PVA and
another water soluble resin may be used in combination. Even in the case
where the mask pattern has a liquid-repellent surface, the liquid
repellency can be further enhanced by performing the plasma treatment or
the like.

[0150]Subsequently, a solution which forms a lyophilic surface is applied
or discharged to form second mask patterns 573 to 575. An organic resin
such as an acrylic resin, a polyimide resin, a melamine resin, a
polyester resin, a polycarbonate resin, a phenol resin, an epoxy resin,
polyacetal, polyether, polyurethane, polyamide (nylon), a furan resin, or
a diallyl phthalate resin, siloxane, or polysilazane can be given as a
typical example of the solution which forms a lyophilic surface. Further,
a solution using a polar solvent such as water, alcohols, ethers,
dimethylformamide, dimethylacetamide, dimethylsulfoxide,
N-methylpyrrolidone, hexamethylphosphamide, chloroform, or methylene
chloride can be used. A droplet discharge method, an ink-jet method, a
spin coating method, a roll coating method, a slot coating method, or the
like can be employed as a method for applying a solution of the second
mask patterns.

[0151]Since the first mask patterns 571 and 572 have liquid-repellent
surfaces, the second mask patterns 573 to 575 are formed in the outer
periphery of the first mask patterns, that is, in a region where the
first mask patterns are not formed.

[0152]Instead of the above steps, the second mask patterns may be formed
by applying the solution which forms a lyophilic surface after drying a
solvent of the first mask patterns. In this case, since the first mask
patterns 571 and 572 have liquid-repellent surfaces, the second mask
patterns 573 to 575 are formed in the outer periphery of the first mask
patterns, that is, in a region where the first mask patterns are not
formed. In addition, a composition of the first mask patterns remains on
the surface of the first insulating film 541 or penetrates into the film.

[0153]Subsequently, the first mask patterns 571 and 572 and the first
insulating film 541 are etched by using the second mask patterns as a
mask to partially expose the source/drain electrodes as shown in FIG. 7C.
A reference numeral 581 denotes a gate insulating film.

[0154]After the second mask patterns are removed, conductive layers 561
and 562 are formed as shown in FIG. 7D.

[0155]Note that the second mask patterns 573 to 575 may be used as
interlayer insulating films without removing, and then, the conductive
layers 561 and 562 may be formed as shown in FIG. 7E.

Embodiment Mode 7

[0156]A droplet discharge apparatus which can be used for pattern
formation in the above embodiment modes is described in this embodiment
mode. In FIG. 24, a region 1830 where one panel is to be formed is shown
in dashed line on a substrate 1800.

[0157]FIG. 24 shows one mode of a droplet discharge apparatus used to form
a pattern such as a wiring. A droplet discharge means 1805 has a head,
and the head has a plurality of nozzles. The case of having three heads
(1803a, 1803b, and 1803c) each provided with ten nozzles is described in
this embodiment mode. However, the number of nozzles and heads can be set
in accordance with treatment area, steps, or the like.

[0158]The heads are connected to a control means 1807, and the control
means controls the heads by a computer 1810, so that a preset pattern can
be drawn. A position of drawing may be determined by, for example, using
a marker 1811 that is formed over the substrate 1800 or the like fixed to
a stage 1831 as a reference point. Alternatively, the position of drawing
may be determined by using an edge of the substrate 1800 as a reference
point. The reference point is detected by an imaging means 1804 such as a
CCD, and changed into a digital signal by an image processing means 1809.
Then, the digital signal is recognized by the computer 1810, and a
control signal is generated and transmitted to the control means 1807.
When the pattern is drawn in this manner, a distance between a pattern
formation face and a tip of the nozzle may be set from 0.1 cm to 5 cm,
preferably, from 0.1 cm to 2 cm, more preferably, approximately 0.1 cm.
Landing accuracy of a droplet is improved by making the distance short as
described above.

[0159]At this time, information on a pattern to be formed over the
substrate 1800 is stored in a storage medium 1808, and a control signal
is transmitted to the control means 1807 based on the information, so
that the heads 1803a, 1803b, and 1803c can be individually controlled. In
other words, droplets including different materials can be discharged
from each nozzle of the heads 1803a, 1803b, and 1803c. For example, the
nozzles of the heads 1803a and 1803b can discharge a droplet including an
insulating film material and the nozzles of the head 1803c can discharge
a droplet including a conductive film material.

[0160]Further, the nozzles of the head can also be individually
controlled. Since the nozzles can be individually controlled, droplets
including different materials can be discharged from a specific nozzle.
For example, one head 1803a can be provided with a nozzle which
discharges a droplet including a conductive film material and a nozzle
which discharges a droplet including an insulating film material.

[0161]In the case of performing droplet discharge treatment on a large
area, such as a formation step of an interlayer insulating film, a
droplet including an interlayer insulating film material is preferably
discharged from all nozzles. Further, a droplet including an interlayer
insulating film material may be discharged from all nozzles of a
plurality of heads. Accordingly, throughput can be improved. Naturally,
in the interlayer insulating film formation step, droplet discharge
treatment may be performed on a large area by discharging a droplet
including an interlayer insulating film material from one nozzle and by
making the nozzle scan the substrate a plurality of times.

[0162]Pattern formation on a large mother glass can be performed by moving
a head in zigzag or shuttling a head. At this time, the head may be made
to relatively scan the substrate a plurality of times. When the head
scans the substrate, the head is preferably inclined toward a moving
direction.

[0163]When a plurality of panels is formed out of a large mother glass,
the head preferably has a width equal to that of one panel. This is
because a pattern can be formed in the region 1830 where one panel is
formed by moving the head once; thus, high throughput can be expected.

[0164]The head may have a width narrower than that of the panel. At this
time, a plurality of heads having a narrow width may be arranged in
series to have a width equal to that of one panel. Bending of the head,
which is concerned as a width of the head becomes broader, can be
prevented from occurring by arranging a plurality of heads having a
narrow width in series. Naturally, a pattern can be formed by moving a
head having a narrow width a plurality of times.

[0165]A step of discharging a droplet of a solution by a droplet discharge
method as described above is preferably performed under reduced pressure.
This is because a solvent of the solution is evaporated during a period
from discharging the solution until the solution lands on an object to be
treated, and thus, both steps of drying and baking the solution can be
omitted. It is preferable to perform the step under reduced pressure,
since an oxide film or the like is not formed on the surface of a
conductor. In addition, the step of dropping a solution may be performed
in a nitrogen atmosphere or an organic gas atmosphere.

[0166]A piezo method can be employed as a droplet discharge method. The
piezo method is utilized also for an inkjet printer since it has superior
ink-droplet controllability and a high degree of freedom for ink
selection. Note that the piezo method includes a bender type (typically,
an MLP (Multi Layer Piezo) type), a piston type (typically, an MLChip
(Multi Layer Ceramic Hyper Integrated Piezo segments) type), a side wall
type, and a roof wall type. Alternatively, a droplet discharge method
using a so-called bubble jet method (thermal method) which makes a
heating element generate heat to generate bubbles, thereby pushing out a
solution may be employed depending on a solvent of a solution.

Embodiment 1

[0167]A mask pattern formed by using laser light is described in this
embodiment with reference to FIGS. 25A and 25B.

[0168]A positive photosensitive resin of 1.5 μm in thickness was
applied to a substrate and was temporarily baked by heating at 90°
C. for 90 seconds. A novolac resin having a photosensitive agent was used
as a positive photosensitive resin.

[0169]Subsequently, the positive photosensitive resin was irradiated with
laser light and exposed to light. Continuous wave Nd:YVO4 was
employed for a laser oscillator at this time. Laser light emitted from
the laser oscillator had a wavelength of 532 nm and a spot of 300
μm×20 μm in size.

[0170]Thereafter, the positive photosensitive resin was developed by using
tetraethylammonium hydroxide (TMAH) of 2.38%.

[0171]TABLE 1 shows the results whether development can be performed or
not with respect to laser power and movement speed of a stage.

[0172]As shown in TABLE 1, development could be performed at stage
movement speeds of from 25 cm/sec to 50 cm/sec when laser power was 6 W,
and development could be performed at stage movement speeds of from 40
cm/sec to 100 cm/sec when laser power was 8 W.

[0173]FIG. 25A shows a surface of a positive photosensitive resin
irradiated with laser light and developed with laser power of 6 W and
stage movement speed of 25 cm/sec, which is observed with an optical
microscope (a reflection bright field mode). FIG. 25B is a schematic
diagram of FIG. 25A. A groove of approximately 400 μm in width is
formed in a region 1901 irradiated with laser light, compared with a
region 1900 not irradiated with laser light. Height of the groove was 1.5
μm when measured with a stylus surface profiler DEKTAK3ST
(manufactured by ULVAC, Inc.)

Embodiment 2

[0174]Next, a method for manufacturing an active matrix substrate and a
display panel therewith is described with reference to FIGS. 17A to 21.
This embodiment is described using a liquid crystal display panel as a
display panel. FIGS. 17A to 17G and FIGS. 18A to 18D schematically show a
longitudinal section structure of a pixel portion and a connection
terminal portion. FIGS. 19 to 21 show a plane structure corresponding to
a line A-B and a line C-D.

[0175]As shown in FIG. 17A, a surface of a substrate 800 is oxidized at a
temperature of 400° C. to form an insulating film 801 having a
thickness of 100 nm. The insulating film serves as an etching stopper
film of a conductive film to be formed later. Subsequently, a first
conductive layer 802 is formed over the insulating film 801 by a droplet
discharge method, and a first photosensitive resin 803 is discharged by a
droplet discharge method to the first conductive layer. Then, the first
photosensitive resin is irradiated with laser light 804 and developed to
form a first mask pattern 805.

[0176]An AN100 glass substrate manufactured by Asahi Glass Co., Ltd. is
used as the substrate 800. As the first conductive layer 802, a solution
in which Ag (silver) particles are dispersed is discharged and dried by
heating at 100° C. for 30 minutes, and is then baked by heating at
230° C. for one hour in an atmosphere with an oxygen concentration
of 10%. As the first photosensitive resin 803, a negative photosensitive
resin is discharged by a droplet discharge method and dried, and is then
temporarily baked. Laser light emitted from Nd:YVO4 laser is used as
the laser light 804.

[0177]Subsequently, the first conductive layer is partially etched by
using the first mask pattern to form a gate wiring layer 811 as shown in
FIG. 17C. The first mask pattern is removed by using a removing solution
A gate wiring layer 812 and a capacitor wiring layer 813 are formed by a
droplet discharge method. Note that FIG. 17C schematically shows a
longitudinal section structure and a plane structure corresponding to a
line A-B and a line C-D is shown in FIG. 19, so it may be referred to as
well.

[0178]A gate insulating film 814 is formed by a plasma CVD method as shown
in FIG. 17D. A silicon oxynitride film (H, 1.8%, N, 2.6%, O, 63.9%, Si,
31.7%) having a thickness of 110 nm is formed as the gate insulating film
814 by a plasma CVD method with the use of SiH4 and N2O (a flow
ratio of SiH4:N2=1:200) in a chamber heated at 400° C.

[0179]A first semiconductor film 815 and a second semiconductor film 816
which shows n-type conductivity are formed. An amorphous silicon film is
formed to have a thickness of 150 nm by a plasma CVD method as the first
semiconductor film 815. After a first oxide film on the surface of the
amorphous silicon film is removed, a semi-amorphous silicon film is
formed to have a thickness of 50 nm by using a silane gas and a phosphine
gas.

[0180]The surface of the second semiconductor film is treated with ozone
water, and a thin silicon oxide film is formed on the surface of a second
oxide film. Subsequently, a silicon oxide film is formed on the surface
of the second semiconductor film by UV light irradiation in an oxygen
atmosphere, a thermal oxidation method, treatment with ozone water or
hydrogen peroxide including a hydroxyl radical, or the like in order to
improve wettability on the surface of the second semiconductor film and
to spread an aqueous solution over an entire surface of the second
semiconductor film. The silicon oxide film can prevent impurities from a
photosensitive material to be applied later from entering the
semiconductor film. A second photosensitive resin 817 is discharged
thereto. As the second photosensitive resin, a negative photosensitive
resin is discharged to the second semiconductor film by a droplet
discharge method and dried, and is then temporarily baked. The second
photosensitive resin 817 is irradiated with laser light 818 and developed
to form second mask patterns 821 and 822 as shown in FIG. 17E.

[0181]The second semiconductor film 816 is etched by using the second mask
patterns to form first semiconductor regions 823 and 824 (source/drain
regions). The second semiconductor film 816 is etched by using a mixed
gas having a flow ratio of CF4:O2=10:9. Thereafter, the second
mask patterns 821 and 822 are removed by using a removing solution.

[0182]Subsequently, a silicon oxide film is formed over the first
semiconductor film and the second semiconductor film by UV light
irradiation in an oxygen atmosphere, a thermal oxidation method,
treatment with ozone water or hydrogen peroxide including a hydroxyl
radical, or the like. Then, a third mask pattern 831 is formed. The third
mask pattern is formed by discharging polyimide over the first
semiconductor regions 823 and 824 and a part of the first semiconductor
film 815 with a droplet discharge method and by heating at 200° C.
for 30 minutes.

[0183]The first semiconductor film 815 is etched by using the third mask
pattern 831 to form a second semiconductor region 832 as shown in FIG.
17G Thereafter, the third mask pattern 831 is removed by using a removing
solution. Note that FIG. 17G schematically shows a longitudinal section
structure and a plane structure corresponding to a line A-B and a line
C-D is shown in FIG. 20, so it may be referred to as well.

[0184]Subsequently, a source electrode layer 841 and a drain electrode
layer 842 shown in FIG. 18A and a source wiring layer 840 shown in FIG.
21 are formed by a droplet discharge method. As the source electrode
layer 841 and the drain electrode layer 842, a solution in which Ag
(silver) particles are dispersed is discharged and dried by heating at
100° C. for 30 minutes and is then baked by heating at 230°
C. for one hour in an atmosphere with an oxygen concentration of 10%. A
first pixel electrode 843 is formed to connect to the drain electrode
layer 842. Here, indium tin oxide containing silicon oxide (ITSO) is
formed by a sputtering method, and a mask pattern is formed by a droplet
discharge method. Then, etching is performed, thereby forming the first
pixel electrode 843 to connect to the drain electrode layer 842.
Alternatively, the first pixel electrode may be formed by discharging the
above material by a droplet discharge method. Note that a plan view
corresponding to a line A-B and a line C-D in FIG. 18A is shown in FIG.
21.

[0185]According to the above steps, an active matrix substrate can be
formed.

[0186]Since a transmissive liquid crystal display panel is manufactured in
this embodiment, the first pixel electrode is made of ITO containing
silicon oxide. Alternatively, a pixel electrode may be formed by forming
a predetermined pattern of a composition containing indium tin oxide
(ITO), zinc oxide (ZnO), tin oxide (SnO2), or the like and by
baking. In the case of manufacturing a reflective liquid crystal display
panel, a composition which mainly contains particles of a metal such as
Ag (silver), Au (gold), Cu (copper), W (tungsten), or Al (aluminum) can
be used.

[0187]An insulating film is formed by a printing method or a spin coating
method to cover the first pixel electrode 843. Then, rubbing is performed
to form an orientation film 851 as shown in FIG. 18B. Note that the
orientation film 851 can be formed by an oblique evaporation method.

[0188]A sealant 860 in the shape of a closed loop is formed by a droplet
discharge method in the periphery of a region where a pixel is formed. A
liquid crystal material is dropped by a dispenser method (dropping
method) inside the closed loop formed with the sealant 860.

[0189]Here, a step of dropping a liquid crystal material is described with
reference to

[0190]FIGS. 22A and 22B. FIG. 22A is a perspective view of a step of
dropping a liquid crystal material with a dispenser 2701, and FIG. 22B is
a cross-sectional view taken along a line A-B in FIG. 22A.

[0191]A liquid crystal material 2704 is dropped or discharged from the
dispenser 2701 to cover a pixel portion 2703 surrounded by a sealant
2702. A liquid crystal layer can be formed by moving the dispenser 2701
or by moving a substrate 2700 with the dispenser 2701 fixed. In addition,
a plurality of dispensers 2701 may be provided to drop a liquid crystal
material at a time.

[0192]As shown in FIG. 22B, the liquid crystal material 2704 can be
selectively dropped or discharged only in a region surrounded by the
sealant 2702.

[0193]Here, the liquid crystal material is dropped in the pixel portion.
However, the liquid crystal material may be dropped on an opposing
substrate side; then, a substrate having the pixel portion may be
attached thereto.

[0194]Subsequently, as shown in FIG. 18C, a liquid crystal layer 864 is
formed by attaching an opposing substrate 863 provided with an
orientation film 861 and a second pixel electrode (opposite electrode)
862 to the substrate 800, performing ultraviolet curing, and filling a
liquid crystal material in vacuum.

[0195]The sealant 860 may be mixed with a filler, and further, the
opposing substrate 863 may be provided with a color filter, a shielding
film (black matrix), or the like. Instead of a dispenser method (a
dropping method), a dip method (a pumping method) that injects the liquid
crystal material by using a capillary phenomenon after attaching the
opposing substrate can be used as a method for forming the liquid crystal
layer 864.

[0196]After removing the gate insulating film 814 formed in each edge
portion of the gate wiring layer 812 and a source wiring layer (not
shown), connection terminals (a connection terminal 872 to be connected
to the gate wiring layer and a connection terminal to be connected to the
source wiring layer which is not shown) are attached with an anisotropic
conductive layer 871 therebetween as shown in FIG. 18D. Further, a
connection portion of each wiring layer and connection terminal is
preferably sealed with a sealing resin. This structure can prevent
moisture from a section from entering and deteriorating the pixel
portion. According to the above steps, a liquid crystal display panel can
be formed.

[0197]According to the above steps, a liquid crystal display panel can be
manufactured. Note that a protective circuit, typically, a diode or the
like for preventing electrostatic damage may be provided between the
connection terminal and the source wiring (gate wiring) or in the pixel
portion. In this case, the protection circuit can be operated as a diode
by manufacturing with a similar step to that of a TFT described above and
by connecting the gate wiring layer of the pixel portion and the drain or
source wiring layer of the diode.

[0198]Note that any of Embodiment Modes 1 to 7 can be applied to this
embodiment. A method for manufacturing a liquid crystal display panel as
a display panel is described in this embodiment; however, the invention
is not limited thereto. The invention can be appropriately applied to an
active display panel including a light-emitting material of an organic
material or an inorganic material as a light emitting layer, such as a
DMD (Digital Micromirror Device), a PDP (Plasma Display Panel), a FED
(Field Emission Display), an electrophoretic display device (electronic
paper), or the like.

Embodiment 3

[0199]Subsequently, a method for manufacturing an active matrix substrate
and a display panel therewith is described with reference to FIGS. 29A to
34. This embodiment is described using a light emitting display panel as
a display panel. FIGS. 29A to 31B schematically show a longitudinal
section structure of a pixel portion and a connection terminal portion.
FIGS. 32 to 34 show a plane structure corresponding to a line A-B, a line
C-D, and a line E-F.

[0200]As shown in FIG. 29A, a surface of a substrate 600 is oxidized at a
temperature of 400° C. to form an insulating film 601 having a
thickness of 100 nm. The insulating film serves as an etching stopper
film of a conductive film to be formed later. Subsequently, first
conductive layers 602 and 603 are formed over the insulating film 601 by
a droplet discharge method, and first photosensitive resins 604 and 605
are applied by a droplet discharge method to the first conductive layers.
Then, the first photosensitive resins are irradiated with laser light 606
and 607 and developed to form first mask patterns 608 and 609 as shown in
FIG. 29B.

[0201]An AN100 glass substrate manufactured by Asahi Glass Co., Ltd. is
used as the substrate 600. As the first conductive layers 602 and 603, a
solution in which Ag (silver) particles are dispersed is discharged and
dried by heating at 100° C. for 30 minutes and is then baked by
heating at 230° C. for one hour in an atmosphere with an oxygen
concentration of 10%. As the first photosensitive resins 604 and 605,
negative photosensitive resins are discharged by a droplet discharge
method and dried, and are then temporarily baked. Laser light emitted
from Nd:YVO4 laser is used as the laser light 606 and 607.

[0202]Subsequently, the first conductive layers are partially etched by
using the first mask patterns 608 and 609 to form gate electrode layers
611 and 612 as shown in FIG. 29C. The first mask patterns are removed by
using a removing solution. A gate wiring layer 613, a connection
conductive layer 614, and a capacitor electrode layer 610 which is shown
in FIG. 32 are formed by a droplet discharge method. Note that FIG. 29C
schematically shows a longitudinal section structure and a plane
structure corresponding to a line A-B, a line C-D, and a line E-F is
shown in FIG. 32, so it may be referred to as well.

[0203]A gate insulating film 615 is formed by a plasma CVD method as shown
in FIG. 29D. A silicon oxynitride film (H, 1.8%, N, 2.6%, O, 63.9%, Si,
31.7%) having a thickness of 110 nm is formed as the gate insulating film
615 by a plasma CVD method with the use of SiH4 and N2O (flow
ratio of SiH4:N2=1:200) in a chamber heated at 400° C.

[0204]A first semiconductor film 616 and a second semiconductor film 617
which shows n-type conductivity are formed. An amorphous silicon film is
formed to have a thickness of from 150 nm by a plasma CVD method as the
first semiconductor film 616. After an oxide film on the surface of the
amorphous silicon film is removed, a semi-amorphous silicon film is
formed to have a thickness of 50 nm by using a silane gas and a phosphine
gas.

[0205]Subsequently, a silicon oxide film is formed over the second
semiconductor film by UV light irradiation in an oxygen atmosphere, a
thermal oxidation method, treatment with ozone water or hydrogen peroxide
including a hydroxyl radical, or the like. Second photosensitive resins
618 and 619 are applied to the second semiconductor film. As a second
mask pattern, a negative photosensitive resin is discharged to the second
semiconductor film by a droplet discharge method and dried, and are then
temporarily baked. The second photosensitive resins 618 and 619 are
irradiated with laser light 620 and 621 respectively and developed to
form second mask patterns 631 to 634 as shown in FIG. 29E.

[0206]The second semiconductor film 617 is etched by using the second mask
patterns 631 to 634 to form first semiconductor regions 635 to 638
(source/drain regions) as shown in FIG. 30A. The second semiconductor
film 617 is etched by using a mixed gas having a flow ratio of
CF4:O2=10:9. Thereafter, the second mask patterns 631 to 634
are removed by using a removing solution.

[0207]Subsequently, a silicon oxide film is formed over the first
semiconductor film and the first semiconductor regions by UV light
irradiation in an oxygen atmosphere, a thermal oxidation method,
treatment with ozone water or hydrogen peroxide including a hydroxyl
radical, or the like. Then, third mask patterns 641 and 642 are
discharged. The third mask patterns are formed by discharging polyimide
to the first semiconductor regions 635 to 638 and a part of the first
semiconductor film 616 with a droplet discharge method and by heating at
200° C. for 30 minutes.

[0208]The first semiconductor film 616 is etched by using the third mask
patterns 641 and 642 to form second semiconductor regions 643 and 644 as
shown in FIG. 30B. Thereafter, the third mask patterns 641 and 642 are
removed by using a removing solution. Note that FIG. 30B schematically
shows a longitudinal section structure and a plane structure
corresponding to a line A-B, a line C-D, and a line E-F is shown in FIG.
33, so it may be referred to as well.

[0209]Subsequently, a third photosensitive resin 651 is discharged or
applied, irradiated with laser light 652, and developed as shown in FIG.
30C. A novolac resin which is a positive photosensitive resin is used as
the third photosensitive resin 651. Accordingly, a fourth mask pattern
653 is formed as shown in FIG. 30D.

[0210]The gate insulating film 615 is etched by using the fourth mask
pattern 653 as a mask to expose a part of the connection conductive layer
614. Then, the fourth mask pattern is removed by using a removing
solution.

[0211]Subsequently, source electrode layers 661 and 663 and drain
electrode layers 662 and 664 shown in FIG. 31A and a source wiring layer
665 and a power supply line layer 666 shown in FIG. 34 are formed by a
droplet discharge method. As these conductive layers, a solution in which
Ag (silver) particles are dispersed is discharged and dried by heating at
100° C. for 30 minutes and is then baked by beating at 230°
C. for one hour in an atmosphere with an oxygen concentration of 10%.
Note that the drain electrode layer 662 is connected to the connection
conductive layer 614. Therefore, the drain electrode layer 662 is
electrically connected to the gate electrode layer 612.

[0212]According to the above steps, an active matrix substrate can be
formed.

[0213]Subsequently, a first pixel electrode 667 is formed to connect to
the drain electrode layer 664. Here, indium tin oxide (ITO), indium tin
oxide containing silicon oxide (ITSO), zinc oxide (ZnO), or the like may
be formed by a sputtering method, and a mask pattern may be formed by a
droplet discharge method. Then, etching is performed, thereby forming the
first pixel electrode 667 to connect to the drain electrode layer 664.
More preferably, indium tin oxide containing silicon oxide is formed by a
sputtering method using a target in which ITO contains silicon oxide of
from 2% to 10% by weight. In addition, an oxide conductive material may
be used, which contains silicon oxide and in which indium oxide is mixed
with zinc oxide (ZnO) of from 2% to 20% by weight. The first pixel
electrode can be formed by discharging the above material with a droplet
discharge method.

[0214]In addition, a composition which mainly contains particles of a
metal such as Ag (silver), Au (gold), Cu (copper), W (tungsten), or Al
(aluminum) can be used in the case of manufacturing a light emitting
display panel having such a structure that generated light is emitted to
an opposite side of the substrate 600, that is, a reflective light
emitting display panel. As another method, the first pixel electrode may
be formed by forming a transparent conductive film or a light-reflective
conductive film by a sputtering method, forming a mask pattern with a
droplet discharge method, and additionally performing an etching process.

[0215]Note that a plan view corresponding to a line A-B, a line C-D, and a
line E-F in FIG. 31A is shown in FIG. 34.

[0216]According to the above steps, a switching TFT 668 and a driving TFT
669 are formed.

[0217]Subsequently, a protective layer 671 of silicon nitride or silicon
nitride oxide and an insulating layer 672 are entirely formed. An opening
is formed through an etching process as shown in FIG. 31B after the
insulating layer 672 is entirely formed by a spin coating method or a
dipping method. The etching is performed simultaneously on the protective
layer 671 and the gate insulating film 615 by using the insulating layer
672 as a mask to expose the first pixel electrode 667 and the gate wiring
layer 613. The etching process is not necessarily required to form the
insulating layer when the insulating layer 672 is formed by a droplet
discharge method.

[0218]In the insulating layer 672, a through-hole is formed to correspond
to a position where a pixel is to be formed in accordance with the first
pixel electrode 667. The insulating layer 672 can be formed by using an
inorganic insulating material such as silicon oxide, silicon nitride,
silicon oxynitride, aluminum oxide, aluminum nitride, or aluminum
oxynitride; acrylic acid; methacrylic acid; a derivative of acrylic acid
or methacrylic acid; a heat-resistant high molecular weight material such
as polyimide, aromatic polyamide, or polybenzimidazole; or inorganic
siloxane including a Si--O--Si bond among compounds that contain silicon,
oxygen, and hydrogen and that are formed by using a siloxane material as
a starting material or an organosiloxane-based insulating material in
which hydrogen bonded with silicon is substituted by an organic group
such as methyl or phenyl. It is preferable to form the insulating layer
by using a photosensitive or non-photosensitive material such as acrylic
or polyimide, since a side face thereof becomes a shape in which the
radius of curvature continuously changes and an upper-layer thin film is
formed without break.

[0219]After a light emitting layer 673 is formed by an evaporation method
or an application method such as a spin coating method or ink-jetting, a
second pixel electrode 674 is formed, thereby forming a light emitting
element 677. The light emitting element 677 is connected to the driving
TFT 669. Note that moisture adsorbed inside or on the surface of the
insulating layer 672 is removed by performing heat treatment at
200° C. under atmospheric pressure before forming the light
emitting layer 673. In addition, heat treatment is performed at from
200° C. to 400° C., preferably, from 250° C. to
350° C. under reduced pressure, and the light emitting layer 673
is preferably formed by a vacuum evaporation method or a droplet
discharge method under reduced pressure without being exposed to
atmospheric air.

[0220]In addition, surface treatment may be performed on the surface of
the first pixel electrode 667 by exposing the surface to oxygen plasma or
irradiating the surface with ultraviolet light.

[0221]The light emitting layer may be made of a charge injection transport
material and a light emitting material containing an organic compound or
an inorganic compound. The light emitting layer includes one or plural
kinds of layers of a low molecular weight organic compound, an
intermediate molecular weight organic compound, and a high molecular
weight organic compound. The light emitting layer may be combined with an
electron injection transport or hole injection transport inorganic
compound.

[0222]As a high electron transporting material among charge injection
transport materials, a metal complex that has a quinoline skeleton or a
benzoquinoline skeleton such as tris(6-quinolinolato)aluminum
[Alq3], tris(5-methyl-6-quinolinolato)aluminum [Almq3],
bis(10-hydroxybenzo[h]-quinolinato)beryllium [BeBq2], or
bis(2-methyl-8-quinolinolato)-4-phenylphenolato-aluminum [BAlq], and the
like can be given. As a high hole transporting material, an aromatic
amine compound (that is, a compound having a benzene ring-nitrogen bond)
such as 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl [α-NPD],
4,4'-bis[N-(3-methylphenyl)-N-phenyl-amino]-biphenyl [TPD],
4,4',4''-tris(N,N-diphenyl-amino)-triphenylamine [TDATA], or
4,4',4''-tris[N-(3-methylphenyl)-N-phenyl-amino]-triphenylamine [MTDATA]
can be specifically given.

[0223]In addition, as a high electron injecting material among charge
injection transport materials, a compound of an alkali metal or an
alkaline earth metal such as lithium fluoride (LiF), cesium fluoride
(CsF), or calcium fluoride (CaF2) can be specifically given. In
addition, the high electron injecting material may be a mixture of a high
electron transporting material such as Alq3 and an alkaline earth
metal such as magnesium (Mg).

[0224]As a high hole injecting material among charge injection transport
materials, metal oxide such as molybdenum oxide (MoOx), vanadium oxide
(VOx), ruthenium oxide (RuOx), tungsten oxide (WOx), or manganese oxide
(MnOx) can be given. In addition, a phthalocyanine compound such as
phthalocyanine [H2Pc] or copper phthalocyanine (CuPC) can be given.

[0225]The light emitting layer may perform color display by providing each
pixel with light emitting layers having different emission wavelength
bands. Typically, a light emitting layer corresponding to each color of R
(red), G (green), and B (blue) is formed. In this case, color purity can
be increased and a pixel portion can be prevented from having a mirror
surface (glare) by providing a light emitting side of a pixel with a
filter (colored layer) which transmits light of an emission wavelength
band. Providing a filter (colored layer) can omit a circular polarizing
plate or the like which is conventionally required and can eliminate the
loss of light emitted from a light emitting layer. Further, change in
hue, which occurs when a pixel portion (display screen) is obliquely
seen, can be reduced.

[0227]On the contrary, a high molecular weight organic light emitting
material is physically stronger than a low molecular weight material and
is superior in durability of the element. In addition, a high molecular
weight material can be formed by application, and therefore, the element
is relatively easily manufactured. A structure of a light emitting
element using a high molecular weight organic light emitting material is
basically the same as that of a light emitting element using a low
molecular weight organic light emitting material, that is, a cathode/an
organic light emitting layer/an anode. However, a two-layer structure is
employed in many cases when a light emitting layer using a high molecular
weight organic light emitting material is formed. This is because it is
difficult to form such a laminated structure as in the case of using a
low molecular weight organic light emitting material. Specifically, the
light emitting element using a high molecular weight organic light
emitting material has a structure of a cathode/a light emitting layer/a
hole transport layer/an anode.

[0228]The emission color is determined by the material of the light
emitting layer. Therefore, a light emitting element that emits desired
light can be formed by selecting an appropriate material of the light
emitting layer. As a high molecular weight electroluminescent material
that can be used to form the light emitting layer, a
polyparaphenylene-vinylene-based material, a polyparaphenylene-based
material, a polythiophen-based material, or a polyfluorene-based material
can be given.

[0229]As the polyparaphenylene-vinylene-based material, a derivative of
poly(paraphenylene vinylene) [PPV], for example,
poly(2,5-dialkoxy-1,4-phenylene vinylene) [RO-PPV],
poly(2-(2'-ethyl-hexoxy)-5-metoxy-1,4-phenylene vinylene) [MEH-PPV],
poly(2-(dialkoxyphenyl)-1,4-phenylene vinylene) [ROPh-PPV], or the like
can be given. As the polyparaphenylene-based material, a derivative of
polyparaphenylene [PPP], for example, poly(2,5-dialkoxy-1,4-phenylene)
[RO-PPP], poly(2,5-dihexoxy-1,4-phenylene), or the like can be given. As
the polythiophene-based material, a derivative of polythiophene [PT], for
example, poly(3-alkylthiophene) [PAT], poly(3-hexylthiophene) [PHT],
poly(3-cyclohexylthiophene) [PCHT], poly(3-cyclohexyl-4-methilthiophene)
[PCHMT], poly(3,4-dicyclohexylthiophene) [PDCHT],
poly[3-(4-octylphenyl)-thiophene] [POPT],
poly[3-(4-octylphenyl)-2,2bithiophene] [PTOPT], or the like can be given.
As the polyfluorene-based material, a derivative of polyfluorene [PF],
for example, poly(9,9-dialkylfluorene) [PDAF], poly(9,9-dioctylfluorene)
[PDOF], or the like can be given.

[0230]Note that a property of a hole injection from an anode can be
enhanced by interposing a high molecular weight organic light emitting
material having hole transporting properties between an anode and a high
molecular weight organic light emitting material having light emitting
properties. This hole transporting material is generally dissolved into
water together with an acceptor material, and the solution is applied by
a spin coating method or the like. Since the hole transporting material
is insoluble in an organic solvent, a laminate with the above-described
organic light emitting material having light emitting properties can be
formed. A mixture of PEDOT and camphor sulfonic acid (CSA) that serves as
an acceptor material, a mixture of polyaniline [PANI] and polystyrene
sulfonic acid [PSS] that serves as an acceptor material, and the like can
be given as the hole transporting high molecular weight organic light
emitting material.

[0231]In addition, the light emitting layer can be formed to emit
monochrome or white light. In the case of using a white light emitting
material, a filter (colored layer) which transmits light having a
specific wavelength is provided on a light emitting side of a pixel,
thereby performing color display.

[0232]In order to form a light emitting layer which emits white light, for
example, Alq3, Alq3 partially doped with Nile red that is a red
light emitting pigment, p-EtTAZ, and TPD (aromatic diamine) are
sequentially laminated by an evaporation method to obtain white light.
When the light emitting layer is formed by an application method using
spin coating, the layer after application is preferably baked by vacuum
heating. For example, an aqueous solution of poly(ethylene
dioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS) may be entirely
applied and baked to form a film that functions as a hole injection
layer. Then, a polyvinyl carbazole (PVK) solution doped with a light
emitting center pigment (such as 1,1,4,4-tetraphenyl-1,3-butadiene (TPB),
4-dicyanomethylene-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM1),
Nile red, or coumarin 6) may be entirely applied and baked to form a film
that functions as a light emitting layer.

[0233]The light emitting layer may be formed to be a single layer. For
example, a 1,3,4-oxadiazole derivative (PBD) capable of transporting
electrons may be dispersed in polyvinyl carbazole (PVK) capable of
transporting holes. Another method to obtain white light emission is to
disperse PBD of 30 wt % as an electron transporting agent and to disperse
four kinds of pigments (TPB, coumarin 6, DCM1, and Nile red) in
appropriate amounts. In addition to the light emitting elements described
here that provide white light emission, a light emitting element that
provides red light emission, green light emission, or blue light emission
can be manufactured by appropriately selecting materials of the light
emitting layer.

[0234]Further, a triplet excitation material containing a metal complex or
the like as well as a singlet excitation light emitting material may be
used for the light emitting layer. For example, among pixels emitting
red, green, and blue light, a pixel emitting red light whose luminance is
reduced by half in a relatively short time is made of a triplet
excitation light emitting material and the rest are made of a singlet
excitation light emitting material. A triplet excitation light emitting
material has a characteristic that the material has a good luminous
efficiency and consumes less power to obtain the same luminance. When a
third excitation light emitting material is used for a red pixel, only
small amount of current needs to be applied to a light emitting element.
Thus, reliability can be improved. A pixel emitting red light and a pixel
emitting green light may be made of a triplet excitation light emitting
material and a pixel emitting blue light may be made of a singlet
excitation light emitting material to achieve low power consumption. Low
power consumption can be further achieved by forming a light emitting
element which emits green light that has high visibility with a triplet
excitation light emitting material.

[0235]A metal complex used as a dopant is an example of a triplet
excitation light emitting material, and a metal complex having platinum
that is a third transition series element as a metal center, a metal
complex having iridium as a metal center, and the like are known. A
triplet excitation light emitting material is not limited to the
compounds. A compound having the above described structure and an element
belonging to any of Groups 8 to 10 of the periodic table as a metal
center can also be used.

[0236]The above described materials for forming the light emitting layer
are just examples. A light emitting element can be formed by
appropriately laminating functional layers such as a hole injection
transport layer, a hole transport layer, an electron injection transport
layer, an electron transport layer, a light emitting layer, an electron
blocking layer, and a hole blocking layer. Further, a mixed layer or a
mixed junction may be formed by combining these layers. The layer
structure of the light emitting layer can be varied. Instead of providing
a specific electron injection region or light emitting region,
modification such as providing an electrode for the purpose or providing
a dispersed light emitting material is acceptable as long as it does not
deviate from the scope of the invention.

[0237]A light emitting element formed with the above described materials
emits light by being biased in a forward direction. A pixel of a display
device formed with a light emitting element can be driven by a simple
matrix mode or an active matrix mode. In any event, each pixel emits
light by applying a forward bias thereto in specific timing; however, the
pixel is in a non-light-emitting state for a certain period. Reliability
of a light emitting element can be improved by applying a backward bias
at this non-light-emitting time. In a light emitting element, there is a
deterioration mode in which emission intensity is decreased under
specific driving conditions or a deterioration mode in which a
non-light-emitting region is enlarged in the pixel and luminance is
apparently decreased. However, progression of deterioration can be slowed
down by alternating driving. Thus, reliability of a light emitting device
can be improved.

[0238]Subsequently, a sealant 676 is formed and sealing is performed by
using a sealing substrate 675. Subsequently, a connection terminal (a
connection terminal 682 to be connected to the gate wiring layer and a
connection terminal to be connected to the source wiring layer which is
not shown) is attached to each edge portion of the gate wiring layer 613
and a source wiring layer (not shown) with an anisotropic conductive
layer 681 therebetween. Further, a connection portion of each wiring
layer and connection terminal is preferably sealed with a sealing resin
683. This structure can prevent moisture from a section from entering and
deteriorating the pixel portion. According to the above steps, a light
emitting display panel can be formed.

[0239]According to the above described steps, a light emitting display
panel can be manufactured. Note that a protective circuit, typically, a
diode or the like for preventing electrostatic damage may be provided
between the connection terminal and the source wiring (gate wiring) or in
the pixel portion. In this case, the protection circuit can be operated
as a diode by manufacturing with a similar step to that of the TFT
described above and by connecting the gate wiring layer of the pixel
portion to the drain or source wiring layer of the diode.

Embodiment 4

[0240]A mode of a light emitting element applicable to the above
embodiments is described with reference to FIGS. 26A to 26D.

[0241]FIG. 26A shows an example of a light emitting element whose first
pixel electrode 11 is made of a light-transmitting oxide conductive
material. The first electrode 11 is made of an oxide conductive material
containing silicon oxide with a concentration of from 1 atomic % to 15
atomic %. An EL layer 16 is formed thereover, which is a laminate of a
hole injection layer and/or a hole transport layer 41, a light emitting
layer 42, and an electron transport layer and/or an electron injection
layer 43. A second pixel electrode 17 is formed with a first electrode
layer 33 containing an alkali metal or alkaline earth metal such as LiF
or MgAg and a second electrode layer 34 made of a metal material such as
aluminum. A pixel of this structure can emit light from the side of the
first pixel electrode 11 as indicated by an arrow in the figure.

[0242]FIG. 26B shows an example of a light emitting element which emits
light through a second pixel electrode 17. A first pixel electrode 11 is
formed with a first electrode layer 35 made of a metal such as aluminum
or titanium or a metal material containing the metal and nitrogen with
concentrations of a stoichiometric composition ratio or less and a second
electrode layer 32 made of an oxide conductive material containing
silicon oxide with a concentration of from 1 atomic % to 15 atomic %. An
EL layer 16 is formed thereover, which is a laminate of a hole injection
layer and/or a hole transport layer 41, a light emitting layer 42, and an
electron transport layer and/or an electron injection layer 43. A second
pixel electrode 17 is formed with a third electrode layer 33 containing
alkali metal or alkaline earth metal such as LiF or CaF and a fourth
electrode layer 34 made of a metal material such as aluminum. Each layer
is formed to have thicknesses of 100 nm or less so that the layer can
transmit light. Accordingly, light can be emitted through the second
pixel electrode 17.

[0243]FIG. 26C shows an example of a light emitting element which emits
light through a first pixel electrode 11 and a structure in which an EL
layer is formed by sequentially laminating an electron transport layer
and/or an electron injection layer 43, a light emitting layer 42, and a
hole injection layer and/or a hole transport layer 41. A second pixel
electrode 17 is formed, from the EL layer 16 side, with a second
electrode layer 32 made of an oxide conductive material containing
silicon oxide with concentrations of from 1 atomic % to 15 atomic % and a
first electrode layer 35 made of a metal such as aluminum or titanium or
a metal material containing the metal and nitrogen with a concentration
of a stoichiometric composition ratio or less. The first pixel electrode
11 is formed with a third electrode layer 33 containing alkali metal or
alkaline earth metal such as LiF or CaF and a fourth electrode layer 34
made of a metal material such as aluminum. Each layer is formed to have
thicknesses of 100 nm or less so that the layer can transmit light.
Accordingly, light can be emitted through the first pixel electrode 11.

[0244]FIG. 26D shows an example of a light emitting element which emits
light through a second pixel electrode 17 and a structure in which an EL
layer is formed by sequentially laminating an electron transport layer
and/or an electron injection layer 43, a light emitting layer 42, and a
hole injection layer and/or a hole transport layer 41. The first pixel
electrode 11 is formed to have a similar structure to that shown in FIG.
25A and to be thick to the extent that the first pixel electrode can
reflect light emitted from the EL layer. The second pixel electrode 17 is
made of an oxide conductive material containing silicon oxide with a
concentration of from 1 atomic % to 15 atomic %. In this structure, the
hole injection layer or hole transport layer 41 is made of inorganic
metal oxide (typically, molybdenum oxide or vanadium oxide). Accordingly,
oxygen to be introduced in forming the second pixel electrode 17 is
supplied and a hole injection property is improved. Thus, drive voltage
can be lowered.

Embodiment 5

[0245]A pixel circuit of a light-emitting display panel as described in
the above embodiments and an operating method thereof are described with
reference to FIGS. 27A to 27F.

[0246]In a pixel shown in FIG. 27A, a signal line 710 and power supply
lines 711 and 712 are arranged in a column direction and a scanning line
714 is arranged in a row direction. In addition, the pixel includes a
switching TFT 701, a driving TFT 703, a current control TFT 704, a
capacitor element 702, and a light emitting element 705.

[0247]A pixel shown in FIG. 27C is different in the way that a gate
electrode of a TFT 703 is connected to a power supply line 712 arranged
in a row direction, but other than that, the pixel has a similar
structure to the pixel shown in FIG. 27A. In other words, equivalent
circuit diagrams of both of the pixels shown in FIGS. 27A and 27C are the
same. However, each power supply line is formed using a conductive layer
in a different layer when the power supply line 712 is arranged in a
column direction (FIG. 27A) and when the power supply line 712 is
arranged in a row direction (FIG. 27C). Here, a wiring connected to the
gate electrode of the driving TFT 703 is focused and the figures are
separately shown in FIGS. 27A and 27C to show that the wirings are formed
in different layers.

[0248]In the pixels shown in FIG. 27A and FIG. 27C, the TFTs 703 and 704
are connected in series in the pixel. A channel length L(703) and a
channel width W(703) of the TFT 703 and a channel length L(704) and a
channel width W(704) of the TFT 704 are preferably set to satisfy
L(703)/W(703): L(704)/W(704)=5 to 6000:1.

[0249]Note that the TFT 703 operates in a saturation region and has a role
of controlling the amount of electric current flowing through the light
emitting element 705, and the TFT 704 operates in a linear region and has
a role of controlling supply of electric current to the light emitting
element 705. It is also preferable from the viewpoint of the
manufacturing steps that both of the TFT's have the same conductivity. In
this embodiment mode, the TFTs are formed to be n-channel TFTs. Further,
the TFT 703 may be a depletion mode TFT as well as an enhancement mode
TFT. In the present invention having the above structure, the TFT 704
operates in a linear region, so that slight variation in Vgs (gate-source
voltage) of the TFT 704 does not affect the amount of electric current of
the light emitting element 705. In other words, the amount of electric
current of the light emitting element 705 is determined by the TFT 703
which operates in a saturation region. According to the above-described
structure, luminance variation of the light emitting element, which is
caused by variation in characteristics of the TFT, can be improved, and a
display device with improved image quality can be provided.

[0250]In the pixels shown in FIGS. 27A to 27D, the TFT 701 is a TFT for
controlling input of a video signal to the pixel. When the TFT 701 is
turned ON, the video signal is inputted to the pixel. Then, voltage of
the video signal is stored in the capacitor element 702. FIGS. 27A and
27C each show a structure in which the capacitor element 702 is provided;
however, the invention is not limited thereto. When a gate capacitor or
the like can be used as the capacitor that can hold a video signal, the
capacitor element 702 may not be provided.

[0251]The pixel shown in FIG. 27B has the same structure as the pixel
shown in FIG. 27A except that a TFT 706 and a scanning line 715 are
added. In the same manner, a pixel shown in FIG. 27D has the same
structure as the pixel shown in FIG. 27C except that a TFT 706 and a
scanning line 715 are added.

[0252]In the TFT 706, ON or OFF is controlled by the scanning line 715
that is newly arranged. When the TFT 706 is turned ON, an electric charge
held in the capacitor element 702 is discharged, and the TFT 704 is
turned OFF. In other words, it is possible to make a state in which
current is forced not to flow through the light emitting element 705 by
disposing the TFT 706. Therefore, the TFT 706 can be referred to as an
erasing TFT. Accordingly, in the structures in FIGS. 27B and 27D, a
lighting period can be started simultaneously with or immediately after a
start of a writing period without waiting for writing of signals in all
pixels. Consequently, a duty ratio can be improved.

[0253]In a pixel shown in FIG. 27E, a signal line 710 and a power supply
line 711 are arranged in a column direction, and a scanning line 714 is
arranged in a row direction. In addition, the pixel includes a switching
TFT 701, a driving TFT 703, a capacitor element 702, and a light emitting
element 705. A pixel shown in FIG. 27F has the same structure as the
pixel shown in FIG. 27E except that a TFT 706 and a scanning line 715 are
added. A duty ratio can be increased by disposing the TFT 706 also in the
structure of FIG. 27F.

[0254]It is preferable to make a semiconductor film of a driving TFT large
specifically in the case of forming a thin film transistor having an
amorphous semiconductor film or the like as in the above embodiment
modes. Therefore, considering an aperture ratio, the pixel shown in FIG.
27E or 27F, which has a small number of TFTs, is preferably used.

[0255]Such an active matrix light emitting device is considered to be
advantageous to low voltage driving when a pixel density is increased
since each pixel is provided with TFTs. On the other hand, a passive
matrix light emitting device in which TFTs are provided for every column
can be formed. In the passive matrix light emitting device, TFTs are not
provided for each pixel; therefore, a high aperture ratio can be
obtained.

[0256]As described above, various pixel circuits can be adopted.

Embodiment 6

[0257]Mounting of driver circuits (a signal line driver circuit 1402 and
scanning line driver circuits 1403a and 1403b) on the display panel
described in the above embodiment is described in this embodiment with
reference to FIGS. 9A to 9C.

[0258]As shown in FIG. 9A, the signal line driver circuit 1402 and the
scanning line driver circuits 1403a and 1403b are mounted on the
periphery of a pixel portion 1401. In FIG. 9A, an IC chip 1405 is mounted
on a substrate 1400 by a COG method as the signal line driver circuit
1402, the scanning line driver circuits 1403a and 1403b, and the like.
Then, the IC chip is connected to an external circuit through an FPC
(flexible printed circuit) 1406.

[0259]As shown in FIG. 9B, in the case of forming a TFT with a SAS or a
crystalline semiconductor, a pixel portion 1401, scanning line driver
circuits 1403a and 1403b, and the like may be integrally formed over a
substrate, and a signal line driver circuit 1402 and the like may be
separately mounted as an IC chip. In FIG. 9B, an IC chip 1405 is mounted
on a substrate 1400 by a COG method as the signal line driver circuit
1402. Then, the IC chip is connected to an external circuit through an
FPC 1406.

[0260]Further, as shown in FIG. 9C, a signal line driver circuit 1402 and
the like may be mounted by a TAB method instead of the COG method. Then,
an IC chip is connected to an external circuit through an FPC 1406. In
FIG. 9C, the signal line driver circuit is mounted by a TAB method;
however, a scanning line driver circuit may be mounted by a TAB method.

[0261]When the IC chip is mounted by a TAB method, a pixel portion can be
largely provided with respect to a substrate, and a frame can be
narrowed.

[0262]The IC chip is formed by using a silicon wafer, but an IC formed
over a glass substrate (hereinafter referred to as a driver IC) may be
provided in place of the IC chip. Since the IC chip is taken out of a
circular silicon wafer, there is limitation on the shape of a mother
substrate. On the contrary, the driver IC has a glass mother substrate
and there is no limitation on the shape. Thus, productivity can be
improved. Therefore, the geometry of the driver IC can be freely set. For
example, when the driver IC is formed to have a long side of from 15 mm
to 80 mm in length, the necessary number of the driver ICs can be reduced
compared with the case of mounting the IC chip. Accordingly, the number
of connection terminals can be reduced and a yield in manufacturing can
be improved.

[0263]The driver IC can be formed by using a crystalline semiconductor
formed over a substrate, and the crystalline semiconductor may be formed
by continuous wave laser light irradiation. A semiconductor film formed
by continuous wave laser light irradiation has few crystal defects and
has crystal grains with large grain diameters. Accordingly, a transistor
having such a semiconductor film has favorable mobility and response
speed and high-speed drive can be performed, which is suitable for the
driver IC.

Embodiment 7

[0264]A method for mounting driver circuits (a signal line driver circuit
1402 and scanning line driver circuits 1403a and 1403b) on the display
panel described in the above embodiments is described in this embodiment
with reference to FIGS. 10A to 10D. A connection method with the use of
an anisotropic conductive material, a wire bonding method, or the like
may be employed as the mounting method, and an example thereof is
described with reference to FIGS. 10A to 10D. Note that an example of
using a driver IC as the signal line driver circuit 1402 and the scanning
line driver circuits 1403a and 1403b is described in this embodiment. An
IC chip can be appropriately used in place of the driver IC.

[0265]FIG. 10A shows an example in which a driver IC 1703 is mounted on an
active matrix substrate 1701 by using an anisotropic conductive material.
Each wiring such as a source wiring or a gate wiring (not shown) and
electrode pads 1702a and 1702b of the wiring are formed over the active
matrix substrate 1701.

[0266]Connection terminals 1704a and 1704b are provided on the surface of
the driver IC 1703, and a protective insulating film 1705 is formed in
the periphery thereof.

[0267]The driver IC 1703 is fixed to the active matrix substrate 1701 with
an anisotropic conductive adhesive 1706. The connection terminals 1704a
and 1704b and the electrode pads 1702a and 1702b are electrically
connected to one another with conductive particles 1707 contained in the
anisotropic conductive adhesive. The anisotropic conductive adhesive is
an adhesive resin in which the conductive particles (with grain diameters
of from 3 μm to 7 μm) are dispersed and contained. An epoxy resin,
a phenol resin, and the like can be given as examples of the anisotropic
conductive adhesive. The conductive particles (with grain diameters of
several μm to several hundred μm) are made from an element of gold,
silver, copper, palladium, and platinum, or alloy particles including the
plural elements. Alternatively, particles having a multilayer structure
of the above-mentioned elements may be used. Further, resin particles
coated with one element of gold, silver, copper, palladium, and platinum,
or an alloy of the plural elements may also be used.

[0268]As a substitute for the anisotropic conductive adhesive, an
anisotropic conductive film that is transferred to a base film can be
used. The conductive particles that are similar to those in the
anisotropic conductive adhesive are dispersed in the anisotropic
conductive film. The size and concentration of the conductive particles
1707 mixed in the anisotropic conductive adhesive 1706 are adjusted
adequately, so that the driver IC can be mounted on the active matrix
substrate in this mode. This mounting method is suitable for methods for
mounting the driver ICs in FIGS. 9A and 9B.

[0269]FIG. 10B shows an example of a mounting method that utilizes
shrinkage of an organic resin. Buffer layers 1711a and 1711b are formed
on the surface of connection terminals 1704a and 1704b of a driver IC by
using Ta, Ti, or the like, and Au is formed to be 20 μm in thickness
thereover by an electroless plating method or the like so as to be bumps
1712a and 1712b. The driver IC can be mounted by interposing a light
curable insulating resin 1713 between the driver IC and the active matrix
substrate and by welding electrodes with pressure with the use of the
shrinkage of the light curable resin. This mounting method is suitable
for methods for mounting the driver ICs in FIGS. 9A and 9B.

[0270]As shown in FIG. 10C, a driver IC 1703 may be fixed to an active
matrix substrate 1701 by using an adhesive 1721, and connection terminals
1704a and 1704b of a CPU and electrode pads 1702a and 1702b over the
wiring substrate are connected to each other by wirings 1722a and 1722b.
Then, sealing is performed with an organic resin 1723. This mounting
method is suitable for a method for mounting the driver IC in FIGS. 9A
and 9B.

[0271]As shown in FIG. 10D, a driver IC 1703 may be provided over an FPC
(flexible printed circuit) 1731 with a wiring 1732 and an anisotropic
conductive adhesive 1706 containing conductive particles 1708
therebetween. This structure is extremely effective when used for an
electronic device that is limited in the size of a chassis such as a
portable terminal. This mounting method is suitable for a method for
mounting the driver IC in FIG. 9C.

[0272]Note that a method for mounting the driver IC is not particularly
limited thereto, and a known COG method, wire bonding method, TAB method,
or reflow processing with the use of solder bumps can be employed. When
reflow processing is performed, it is preferable that a substrate used
for a driver IC or an active matrix substrate is made of highly
heat-resistant plastic, typically, a polyimide substrate, an HT substrate
(manufactured by Nippon Steel Chemical Co., Ltd.), ARTON made of a
norbornene resin with a polar group (manufactured by JSR Corporation), or
the like.

Embodiment 8

[0273]This embodiment describes a driver circuit in the case of forming a
scanning line side driving circuit over a substrate 1400 as shown in
FIGS. 9B and 9C by forming a semiconductor layer of a SAS in the display
panel described in Embodiment 6.

[0274]FIG. 14 is a block diagram of a scanning line side driver circuit
including an n-channel type TFT using a SAS in which field effect
mobility of from 1 cm2/Vsec to 15 cm2/Vsec is obtained.

[0275]A block denoted by reference numeral 1500 in FIG. 14 corresponds to
a pulse output circuit for outputting a sampling pulse for one stage, and
a shift register includes n pulse output circuits. A pixel is connected
at the end of buffer circuits 1501 and 1502.

[0276]FIG. 15 shows a specific structure of the pulse output circuit 1500,
and the circuit includes n-channel type TFTs 3601 to 3613. The size of
the TFT may be determined in consideration of operating characteristics
of the n-channel type TFTs using a SAS. When a channel length is set to
be 8 μm, for example, a channel width can be set in the range of from
10 μm to 80 μm.

[0277]FIG. 16 shows a specific structure of the buffer circuit 1501. The
buffer circuit includes n-channel type TFTs 3620 to 3635 in the same
manner. The size of the TFT may be determined in consideration of
operating characteristics of the n-channel type TFTs using a SAS. When a
channel length is set to be 10 μm, for example, a channel width can be
set in the range of from 10 μm to 1800 μm.

Embodiment 9

[0278]A display module is described in this embodiment. Here, a liquid
crystal module is described with reference to FIG. 23 as an example of a
display module.

[0279]An active matrix substrate 1601 and an opposing substrate 1602 are
fixed to each other with a sealant 1600, and a pixel portion 1603 and a
liquid crystal layer 1604 are provided therebetween to form a display
region.

[0280]A colored layer 1605 is required to perform color display. In the
case of RGB system, a colored layer corresponding to each color of red,
green, and blue is provided corresponding to each pixel. Polarizing
plates 1606 and 1607 are provided outside the active matrix substrate
1601 and the opposing substrate 1602. In addition, a protective film 1616
is formed on the surface of the polarizing plate 1606, which relieves
impact from outside.

[0281]A connection terminal 1608 provided for the active matrix substrate
1601 is connected with a wiring substrate 1610 through an FPC 1609. The
FPC or a connection wiring is provided with a pixel driver circuit (an IC
chip, a driver IC, or the like) 1611, and an external circuit 1612 such
as a control circuit or a power supply circuit is incorporated in the
wiring substrate 1610.

[0282]A cold cathode fluorescent tube 1613, a reflecting plate 1614, and
an optical film 1615 are a backlight unit and serve as a light source to
project light on a liquid crystal display panel. The liquid crystal
panel, the light source, the wiring substrate, the FPC, and the like are
held and protected by a bezel 1617.

[0283]Note that any of Embodiment Modes 1 to 7 can be applied to this
embodiment. A liquid crystal display module is described as a display
module in this embodiment; however, the invention is not limited thereto.
The invention can be appropriately applied to a display module such as a
DMD (Digital Micromirror Device), a PDP (Plasma Display Panel), a FED
(Field Emission Display), an electrophoretic display device (electronic
paper), and the like.

Embodiment 10

[0284]A display module is described in this embodiment. Here, a cross
sectional view of a light emitting display module as an example of a
display module is shown in FIGS. 35A to 35C.

[0285]FIG. 35A shows a cross section of a light emitting display module in
which an active matrix substrate 1201 and a sealing substrate 1202 are
fixed to each other with a sealant 1200. A pixel portion 1203 is provided
therebetween to form a display region.

[0286]A space 1204 is formed between the sealing substrate 1202 and the
pixel portion 1203. The entry of moisture or oxygen can be further
prevented by filling the space with an inert gas, for example, a nitrogen
gas or forming a light-transmitting resin having a highly water absorbing
material in the space. In addition, a light-transmitting and highly water
absorbing resin may be formed. Even when light from a light emitting
element is emitted to a second substrate side, a light emitting display
module can be formed without decreasing transmittance owing to a
light-transmitting resin.

[0287]In addition, at least a pixel portion of a module is preferably
provided with a polarizing plate or a circularly polarizing plate (a
polarizing plate, a quarter-wave plate, and a half-wave plate) to enhance
contrast. When display is recognized from a sealing substrate 1202 side,
a quarter-wave plate and a half-wave plate 1205, and a polarizing plate
1206 may be sequentially provided over the sealing substrate 1202.
Further, an anti-reflective film may be provided over the polarizing
plate.

[0288]When display is recognized from both sides of the sealing substrate
1202 and the active matrix substrate 1201, the surface of the active
matrix substrate is preferably provided with a quarter-wave plate and a
half-wave plate, and a polarizing plate in the same manner.

[0289]A connection terminal 1208 provided for the active matrix substrate
1201 is connected with a wiring substrate 1210 through an FPC 1209. The
FPC or a connection wiring is provided with a driver circuit 1211 (an IC
chip, a driver IC, or the like), and an external circuit 1212 such as a
control circuit or a power supply circuit is incorporated in the wiring
substrate 1210.

[0290]As shown in FIG. 35B, a colored layer 1207 can be provided between a
pixel portion 1203 and a polarizing plate or a pixel portion and a
circularly polarizing plate. In this case, full color display can be
performed by providing the pixel portion with a light emitting element
which can emit white light and by separately providing with colored
layers showing RGB. In addition, full color display can be performed by
providing the pixel portion with a light emitting element which can emit
blue light and by separately providing a color conversion layer or the
like. In addition, each pixel portion can be provided with light emitting
elements which emit red, green, and blue light, and the colored layer
1207 can be used. Such a display module has high color purity of each RBG
and can perform high-definition display.

[0291]FIG. 35C shows the case of sealing an active matrix substrate and a
light emitting element with the use of a protective film 1221 of a film,
a resin, or the like without using an opposing substrate, different from
FIG. 35A. The protective film 1221 is provided to cover a pixel electrode
in a pixel portion 1203. As the protective film, an organic material such
as an epoxy resin, a urethane resin, or a silicone resin can be used. In
addition, the protective film may be formed by dropping a polymer
material with a droplet discharge method. In this embodiment, an epoxy
resin is discharged using a dispenser and is dried. Further, an opposing
substrate may be provided over the protective film. The rest of the
structure is similar to that of FIG. 35A.

[0292]A display device can be reduced in weight, size, and thickness by
sealing without using an opposing substrate as described above.

[0293]In the module of this embodiment, the wiring substrate 1210 is
mounted with the use of the FPC 1209; however, the present invention is
not necessarily limited to the structure. The pixel driver circuit 1211
and the external circuit 1212 may be directly mounted on the substrate by
using a COG (Chip on Glass) method.

[0294]Note that any of Embodiment Modes 1 to 7 can be applied to this
embodiment. A light emitting display module is described as a display
module in this embodiment; however, the invention is not limited thereto.
The invention can be appropriately applied to a display module such as a
DMD (Digital Micromirror Device), a PDP (Plasma Display Panel), a FED
(Field Emission Display), an electrophoretic display device (electronic
paper), and the like.

Embodiment 11

[0295]A drying agent of the display panel described in the above
embodiment is described in this embodiment with reference to FIGS. 28A to
28C.

[0296]FIG. 28A is a surface view of a display panel, and FIG. 28B is a
cross-sectional view taken along a line A-B in FIG. 28A and FIG. 28C is a
cross-sectional view taken along a line C-D in FIG. 28A.

[0297]As shown in FIG. 28A, an active matrix substrate 2800 and an
opposing substrate 2801 are sealed with a sealant 2802. A pixel region is
provided between the active matrix substrate and the opposing substrate.
The pixel region is provided with a pixel 2807 in a region at the
intersection of a source wiring 2805 and a gate wiring 2806. A drying
agent 2804 is provided between the pixel region and the sealant 2802. In
the pixel region, a drying agent 2814 is provided over the gate wiring or
the source wiring. Here, the drying agent 2814 is provided over the gate
wiring, but it can be provided over the gate wiring and the source
wiring.

[0298]It is preferable to use a substance that adsorbs water (H2O) by
chemical adsorption like oxide of alkaline earth metal such as calcium
oxide (CaO) or barium oxide (BaO) as the drying agents 2804 and 2814.
However, not limiting thereto, a substance that adsorbs water by physical
adsorption such as zeolite or silica gel can also be used.

[0299]The drying agent can be fixed to the substrate with a granular
drying agent contained in a highly moisture permeable resin. As the
highly moisture permeable resin, the following can be given: an acrylic
resin such as ester acrylate, ether acrylate, ester urethane acrylate,
ether urethane acrylate, butadiene urethane acrylate, special urethane
acrylate, epoxy acrylate, amino resin acrylate, or acrylic resin
acrylate. In addition, an epoxy resin such as a bisphenol A type liquid
resin, a bisphenol A type solid resin, a resin containing bromo-epoxy, a
bisphenol F type resin, a bisphenol AD type resin, a phenol type resin, a
cresol type resin, a novolac type resin, a cyclic aliphatic epoxy resin,
an epibis type epoxy resin, a glycidyl ester resin, a glycidyl amine
resin, a heterocyclic epoxy resin, or a modified epoxy resin can be used.
In addition, other substances may be used. For example, an inorganic
substance such as siloxane, or the like may be used.

[0300]Further, a solidified composition in which a molecule that can
absorb water by chemical absorption is mixed in an organic solvent, or
the like can be used as a water absorbing substance.

[0301]Note that a more highly moisture permeable substance than a
substance used as the sealant is preferably selected as the highly
moisture permeable resin or the inorganic substance.

[0302]In the light emitting device according to the invention as described
above, external water mixed in the light emitting device can be absorbed
before the water reaches a region provided with a light emitting element.
Accordingly, the deterioration of an element provided for the pixel, for
example, a light emitting element due to water can be suppressed.

[0303]As shown in FIG. 28B, the drying agent 2804 is provided between the
sealant 2802 and the pixel region 2803 in the periphery of the display
panel. In addition, the display panel can be thinned by providing the
opposing substrate or the active matrix substrate with a depression and
providing the depression with the drying agent 2804.

[0304]As shown in FIG. 28C, a semiconductor region 2811 that is a part of
a semiconductor element for driving a display element, a gate wiring
2806, a source wiring 2805, and a pixel electrode 2812 are formed in the
pixel 2807. In the pixel portion of a display panel, the drying agent
2814 is provided for a region of the opposing substrate overlapped with
the gate wiring 2806. The gate wiring is two to four times as wide as the
source wiring. Therefore, an aperture ratio is not decreased by providing
the drying agent 2814 over the gate wiring 2806 that is a non display
region, and entry of moisture into the display element and the
deterioration caused thereby can be suppressed. In addition, a display
panel can be thinned by providing the opposing substrate with a
depression and providing the depression with the drying agent.

Embodiment 12

[0305]According to the invention, it is possible to form a semiconductor
device having a circuit in which semiconductor elements with a minute
structure are highly integrated, typically, a signal line driver circuit,
a controller, a CPU, a converter of an audio processing circuit, a power
supply circuit, a transmit and receive circuit, a memory, or an amplifier
of an audio processing circuit. Further, a system-on-chip can be
manufactured, in which circuits such as an MPU (microcomputer), a memory,
and an I/O interface constituting a system (function circuit) are mounted
on one chip in monolithic, and which can realize high speed, high
reliability, and low power consumption.

Embodiment 13

[0306]Various electronic devices can be manufactured by incorporating the
semiconductor device described in Embodiment 9 or 10 in a chassis.
Examples of electronic devices can be given as follows: a television set,
a camera such as a video camera or a digital camera, a goggle type
display (head mounted display), a navigation system, an audio reproducing
device (a car audio, an audio component, or the like), a notebook
personal computer, a game machine, a personal digital assistant (a mobile
computer, a cellular phone, a portable game machine, an electronic book,
or the like), an image reproducing device including a recording medium
(specifically, a device capable of processing data in a recording medium
such as a Digital Versatile Disc (DVD) and having a display that can
display the image of the data), and the like. Here, a television set and
a block diagram thereof are shown in FIG. 12 and FIG. 11, respectively
and a digital camera is shown in FIG. 13 as typical examples of the
electronic devices.

[0307]FIG. 11 is a block diagram showing a general structure of a
television set that receives analog television broadcasting. In FIG. 11,
the airwaves for television broadcasting received by an antenna 1101 are
inputted to a tuner 1102. The tuner 1102 generates and outputs
intermediate frequency (IF) signals by mixing the high frequency
television signals inputted from the antenna 1101 with
locally-oscillating frequency signals that are controlled in accordance
with the desired reception frequency.

[0308]The IF signals taken out by the tuner 1102 are amplified to the
required voltage by an intermediate frequency amplifier (IF amplifier)
1103. Thereafter, the amplified IF signals are detected by a image
detection circuit 1104 and an audio detection circuit 1105. The image
signals outputted from the image detection circuit 1104 are separated
into luminance signals and chrominance signals by an image processing
circuit 1106. Further, the luminance signals and the chrominance signals
are subjected to the predetermined image signal processing to be image
signals, so that the image signals are outputted to an image output
portion 1108 of a display device that is a semiconductor device of the
invention, typically, a liquid crystal display device, a light emitting
device, a DMD (digital micromirror device), a PDP (plasma display panel),
an FED (field emission display), an electrophoretic display device (an
electronic paper), or the like.

[0309]The signals outputted from the audio detection circuit 1105 are
subjected to processing such as FM demodulation in an audio processing
circuit 1107 to be audio signals. The audio signals are then amplified
appropriately to be outputted to an audio output portion 1109 of a
speaker or the like.

[0310]The television set according to the invention may be applicable to
digital broadcastings such as terrestrial digital broadcasting, cable
digital broadcasting, and BS digital broadcasting as well as analog
broadcastings such as terrestrial broadcasting in a VHF band, a UHF band,
or the like, cable broadcasting, and BS broadcasting.

[0311]FIG. 12 is a front perspective view of the television set, which
includes a chassis 1151, a display portion 1152, a speaker portion 1153,
an operational portion 1154, a video input terminal 1155, and the like.
The television set shown in FIG. 12 has the structure as shown in FIG.
11.

[0312]The display portion 1152 is an example of the image output portion
1108 in FIG. 11, which displays images.

[0313]The speaker portion 1153 is an example of the audio output portion
in FIG. 11, which outputs sound.

[0314]The operational portion 1154 is provided with a power source switch,
a volume switch, a channel select switch, a tuning switch, a selection
switch, and the like to turn on and off the television set, select
images, control sound, select a tuner, and the like, respectively by
holding the switches down. Note that the above-described selections can
be carried out also by a remote-control operation unit, though not shown
in the drawing.

[0315]The video input terminal 1155 inputs image signals into the
television set from an external portion such as a VTR, a DVD, or a game
machine.

[0316]In the case of a wall-mounted television set, a portion for hanging
on walls is provided on the rear of the body thereof.

[0317]A television set can be manufactured at low cost with high
throughput and yield by applying the display device that is an example of
a semiconductor device according to the invention to the display portion
of the television set. In addition, a television set can be manufactured
at low cost with high throughput and yield by applying a semiconductor
device according to the invention to a CPU for controlling an image
detection circuit, an image processing circuit, an audio detection
circuit, and an audio processing circuit of a television set.
Consequently, such a television is widely applicable particularly to
large area display mediums such as wall-mounted television set,
information display boards used in railway stations, airports, and the
like, and advertisement display boards on the streets.

[0318]FIGS. 13A and 13B show an example of a digital camera FIG. 13A is a
front perspective view of the digital camera, and FIG. 13B is a rear
perspective view thereof. In FIG. 13A, a digital camera is provided with
a release button 1301, a main switch 1302, a viewfinder window 1303,
flash 1304, a lens 1305, a lens barrel 1306, and a chassis 1307.

[0319]In FIG. 13B, the digital camera is provided with a viewfinder
eyepiece 1311, a monitor 1312, and an operational button 1313.

[0320]When the release button 1301 is held halfway down, a focus
adjustment mechanism and an exposure adjustment mechanism are operated.
Subsequently, holding the release button all the way down releases a
shutter.

[0321]The digital camera is turned on or off by pressing or rotating the
main switch 1302.

[0322]The viewfinder window 1303 is disposed above the lens 1305 on the
front face of the digital camera, and is used to check a shooting range
and a focusing point through the viewfinder eyepiece shown in FIG. 13B.

[0323]The flash 1304 is disposed at the upper portion of the front face of
the digital camera body. In the case of photographing a subject of the
low luminance level, auxiliary light is emitted simultaneously when the
release button is held down and the shutter is released.

[0324]The lens 1305 is disposed on the front of the digital camera. The
lens is made of a focusing lens, a zoom lens, and the like. An optical
shooting system includes the lens along with a shutter and an aperture,
which are not shown in the drawing. An image sensing device such as a CCD
(charge coupled device) is provided at the rear of the lens.

[0325]The lens barrel 1306 is used for shifting the lens position to focus
the focusing lens, the zoom lens, and the like on a subject. When taking
a picture, the lens barrel is protruded from the body so that the lens
1305 is shifted toward a subject. When carrying the digital camera, the
lens 1305 is stored inside the main body to be reduced in size. Note
that, although the lens can be zoomed in to enlarge a subject by shifting
the lens barrel in this embodiment, the invention is not limited to the
structure. The invention is applicable to a digital camera that can take
close-up pictures without zooming a lens due to a structure of an optical
shooting system inside the chassis 1307.

[0326]The viewfinder eyepiece 1311 is provided at the upper portion of the
rear of the digital camera, through which the shooting range and the
focusing point are checked by sight.

[0327]The operational button 1313 is a button for various kinds of
functions and is provided on the rear of the digital camera. The
operational button includes a setup button, a menu button, a display
button, a functional button, a selection button, and the like.

[0328]A digital camera can be manufactured at low cost with high
throughput and yield by applying the display device that is one
embodiment of a semiconductor device according to the invention to a
monitor of the digital camera A digital camera can be manufactured at low
cost with high throughput and yield by applying a CPU that is an example
of the semiconductor device according to the invention to a CPU for
processing in response to input operation of various functional buttons,
a main switch, a release button, and the like, a CPU for controlling
various circuits such as a circuit for autofocusing and autofocusing
adjustment, a timing control circuit for controlling electric flash drive
and CCD drive, an imaging circuit for generating an image signal from a
signal that is photoelectrically converted by an imaging device such as a
CCD, an A/D converter circuit for converting an image signal generated in
an imaging circuit into a digital signal, and a memory interface for
writing and reading image data in a memory, and the like.